Christmas Songs Guitar Chords: 13 Carols You Can Play Tonight

Thirteen Christmas songs you can play on guitar right now, ordered from three open chords up to a jazzy handful, each with the actual chords, the capo move if there is one, and the timing quirk that trips people up even after they know every shape. Start with Jingle Bells at the top and work down toward All I Want for Christmas Is You as the changes get faster and the chords get less familiar.

Quick Reference: All Thirteen Songs

The order above runs roughly easiest to hardest, based on how many chords each song needs, whether a dominant seventh or barre shape shows up, and how quickly the chords change. Jingle Bells at the top never leaves three open chords. All I Want for Christmas Is You at the bottom is built on jazz voicings in its original recording, so the version below is a simplified strumming arrangement rather than the full studio chart. Everything in between sits somewhere along that same scale.

What You Need Before You Start

Every song on this list is built from a small pool of open chords, plus two or three dominant sevenths that show up once you get past the simplest carols. If any of these are shaky, spend ten minutes on them before you touch a song, because a slow chord change hurts a Christmas strum more than a wrong note ever will.

G major

C major

D major

E minor

A minor

Three of these songs also lean on dominant sevenths, which sound unresolved on their own but pull hard into the next chord, which is exactly the job they do in a carol.

D7, G7 and A7

Two songs further down this list, Feliz Navidad in its original key and O Come All Ye Faithful, also call for an open A major, which is worth having ready alongside the dominant sevenths above.

A major

If G, C, D, Em and Am are already solid, you can play seven of the thirteen songs below without learning anything new. The rest add one dominant seventh, one A major, or one barre chord at a time, so nothing on this list asks you to learn more than a chord or two before you can play the whole song.

Jingle Bells

Chords: G, C, D. No capo, no barre, and the whole song sits on those three shapes. This is the easiest song on the list and a reasonable place to start if you are new to guitar entirely, since almost everyone already knows the melody and can hear immediately whether a chord change landed on time.

The verse rocks between G and D, the way the tune itself rocks between two neighboring notes, and the "oh what fun" line is where C shows up, giving the ear a brief lift before the progression resolves back to G. If reading a full chord sheet feels like too much at once, an even simpler two chord version exists using just C and G7, which loses some of the color but keeps the song recognizable while you are still building up your chord vocabulary.

The part that actually trips people up is not the chords but the strum. The melody has a bouncy, dotted rhythm, and a flat, even down up strum sounds correct but feels stiff next to it. Accent the first beat of each bar a little harder than the rest and let the others sit back, and the strum starts to bounce the way the melody does.

Deck the Halls

Chords: G, Em, C, D. No capo. This carol is commonly taught in two different keys, C or G, and the G version is worth learning first here because it reuses the Em shape you will need again in three more songs further down this list.

In the key of G, the verse moves G to Em on "deck the halls with boughs of holly," across to C on the "fa la la la la" answer, then D back to G to close the phrase. The "tis the season" line repeats that same G to Em movement, and "don we now our gay apparel" is where D leads back into G for the close. Every chord change lands right on a strong beat, which makes this one of the more forgiving songs on the list for practicing clean, on time transitions.

The strumming pattern is intentionally basic, essentially one strum per half measure, and the song sounds complete without any embellishment. Save your energy for getting the Em to C change smooth, since that is the one transition here that involves moving every finger at once rather than sliding a single finger across.

Away in a Manger

Chords: G, C, D, D7, Am. No capo. This carol is in 3/4 time, so count it in threes rather than the four count that most of the songs above and below it use. The verse structure repeats a simple G, G, C, G pattern for the opening line, then D, D, C, G to close it, with D7 available in place of plain D wherever you want a slightly stronger pull back to G. If D7 feels like a stretch this early, staying on plain D loses none of the song's shape.

Some versions of this carol are taught in the key of A instead, using only A, D and E, which trades the D7 color for a genuinely three chord arrangement. Either version works for a family sing along, and the A version is worth switching to if your voice sits more comfortably in that range.

Because it is a lullaby, the temptation is to strum it exactly like a 4/4 pop song out of habit. Waltz time wants a strong first beat and two lighter beats after it, down, up up, rather than four even strokes, and that single change in feel is most of what separates a competent version from one that actually sounds like a lullaby.

Silent Night

Chords: G, C, D. No capo. Also in 3/4 time, and also built from the same three open chords as Jingle Bells, which makes it worth learning back to back with that song even though the two feel completely different.

The verse follows the melody closely: G under "silent night, holy night," D under "all is calm, all is bright," C under "round yon virgin, mother and child," and back to G to resolve "holy infant so tender and mild." That G to D to C to G shape repeats through the rest of the carol with only small variations, so once the first line is under your fingers the rest follows the same pattern.

This is one of the few songs on this list that genuinely suits fingerpicking as well as strumming. A simple thumb and finger pattern, thumb on the bass note of each chord and fingers picking the top three strings in order, fits the carol's slow, hushed character better than a full strum does, and it is worth trying both ways to see which one you prefer for this particular song.

The First Noel

Chords: G, D, C, Bm, Am. No capo. This carol is written in 6/8 time, which means you count to six rather than three or four, with a natural lean on beats one and four that gives it a gentle, rolling feel rather than a strict march.

A simplified beginner arrangement swaps out Bm and just uses G, D, C and Am, since Bm is the one barre chord this song calls for and it is easy to substitute around. If you want the full sound including Bm, it is worth learning the shape properly rather than avoiding it forever, since it reappears in Feliz Navidad further down this list. Every way to play Bm is a good next stop if that chord is new to you.

Like Silent Night, this carol suits fingerpicking better than a hard strum, and several well known recorded versions use exactly that approach. If you strum it, keep the pattern light, since a heavy strum fights against the song's rolling 6/8 feel rather than supporting it.

God Rest Ye Merry Gentlemen

Chords: Em, C, B7, Am, G, D. No capo. This is the one minor key carol on this list, and its darker, more dramatic sound compared to Silent Night or Away in a Manger comes directly from that: most of this list sits in a major key, and this one does not.

The verse runs Em, C, B7 twice, then moves through Am, G, Em, D to close the phrase, with the chorus following as G, B7, Em, D. B7 is a new shape here, a four finger chord built from the fifth, fourth, third and first strings, and it is the trickiest chord on this list so far. A useful shortcut when moving between Em and B7 is to keep your second finger anchored on the second fret of the A string the whole time, since both chords use it in the same spot, which turns a four finger jump into a much smaller movement.

B7

If B7 is more than you want to take on right now, a simpler beginner arrangement of this carol exists using Am, E, F, Dm, C and G instead, which trades some of the traditional harmony for chords you may already know from other songs on this list. Either way, this carol rewards a slightly slower, more deliberate strum than the brighter major key songs above it, since rushing tends to blur the minor color that makes it distinctive.

O Come All Ye Faithful

Chords: G, D, Em, A, C. No capo. In the key of G, a common arrangement runs an intro of G, C, D, G, C, D, then G to D under the opening line, moving to Em, A, D, A, D under the "o come ye, o come ye to Bethlehem" phrase that follows.

This carol is commonly taught in several different keys, including versions in D major that lean on Bm and A, and versions in F major built around F, C and Dm, so if a chord sheet you find elsewhere does not match what is above, it is very likely just a different key rather than a wrong source. The G major version here is worth learning first since every chord in it, including A major, is one you need again for Feliz Navidad further down this list.

The melody has a triumphant, marching character, and a firm, confident strum supports that better than a soft one does. Because the chord changes come roughly once per bar rather than twice, this carol is a reasonable one to practice singing along to out loud while you strum, since you have slightly more time between changes to catch your breath than in some of the faster songs on this list.

We Wish You a Merry Christmas

Chords: G, C, A7, D7, Am. No capo. In 3/4 time, and this one has a genuine harmonic trick worth knowing about before you learn it: the progression modulates briefly rather than sitting on the same handful of chords the way most carols do.

In the key of G, a common version runs G, C, A7, D7, G, C, Am, D7, G across the verse, so unlike the songs above, A7 makes its first appearance on this list here and Am shows up in a different spot than it did in Away in a Manger. That extra movement is exactly what gives this carol its slightly more triumphant, "we're really going somewhere" feel compared to a static three chord song.

Because the chords change on almost every bar and the song is fast in 3/4, this is a good one to practice with a metronome once the shapes themselves are comfortable, since the challenge here is speed of the changes rather than the shapes being unfamiliar. How to use a metronome for rhythm guitar covers exactly that kind of practice.

Santa Claus Is Coming to Town

Chords: G, Em, C, D7, A, A7. No capo required, though a capo can help match a specific recording's key. This one has a swing, big band feel rather than a straight carol feel, since the most famous versions lean on a shuffled rhythm rather than even eighth notes.

A beginner friendly arrangement in G alternates G and C early on, then brings in Em, D7 and eventually A and A7 as the song builds, all without needing a single barre chord. Versions arranged in other keys sometimes call for F#m or Bm7, and if you run into one of those, an easier no barre substitute is usually offered right alongside it, since this is a song commonly taught with a beginner friendly alternative built in.

The swing feel is the real challenge here, not the chords. Instead of a straight down up strum, the underlying rhythm has a long short, long short bounce to it, closer to how you would clap along to a big band record than to a folk song. Listening to a recorded version while you strum along is the fastest way to feel that bounce rather than reading it.

Rockin' Around the Christmas Tree

Chords: G, Em, C, D7, Am7. No capo, though the original recording sits in a different key and is often simplified into G or F for guitar. The G version keeps things approachable: the intro runs G, Em, C, D7, and the verse leans on G moving to D7, with Am7 and D7 covering the "mistletoe" section before the progression circles back.

This song is genuinely more complex than a typical three chord carol, both in how many chords it uses and in how the progression moves, and that complexity is part of why it still sounds fresh compared to the older carols on this list. It rewards the extra effort of learning it properly rather than settling for a simplified two chord version.

The strum itself is syncopated, meaning some of the chord changes land on the upbeat rather than squarely on beat one, which is what gives the song its "hop." If your version sounds correct but flat, it is very often this syncopation that is missing rather than a wrong chord. Try clapping the rhythm of "rockin' around the Christmas tree" on its own before you add the guitar back in, and the off beat feel becomes much easier to locate.

Feliz Navidad

Chords in the original key: D, G, A, Bm. No capo needed in that key, though a capo on the 2nd fret lets you play the easier G, C, D and Bm shapes while still sounding in the recorded key, which is the arrangement most beginners are taught. The song's underlying groove is an eighth note backbeat rather than a folk strum, closer in feel to Santa Claus Is Coming to Town than to a traditional carol.

The one chord that gives most players trouble here is Bm, since everything else in this song is an open chord. If Bm is new to you, every way to play Bm walks through the full barre shape as well as easier substitutes, and it is worth the ten minutes since Bm also appears in The First Noel above.

Playing solid rhythm with a convincing backbeat feel is the actual difficulty in this song, more than the chords themselves. Keep your strumming hand moving in a steady eighth note motion even over the beats where you are not actually striking the strings, since that constant hand motion is what keeps a backbeat groove locked in rather than rushing or dragging.

Have Yourself a Merry Little Christmas

Chords: C, Am, Dm, G7. No capo. This is a slower, more reflective ballad than anything else on this list, and the chord progression reflects that: C, Am, Dm, G7 repeating through most of the verse, moving through a minor feel before resolving back to C by way of that G7.

If G7 feels early to introduce, a plain G chord in its place still works and loses only a small amount of the harmonic pull back to C. Dm is the one genuinely new shape here if everything above this song has been comfortable, and it is worth learning properly since it recurs in plenty of other minor key ballads beyond this one.

Because the song is slow, there is nowhere to hide a rushed or sloppy chord change the way a fast strum can sometimes cover one up. Practice this one at a genuinely slow tempo first, letting each chord ring fully before you move to the next, rather than trying to play it at performance speed from the start.

All I Want for Christmas Is You

Chords, full recording: a run of jazz voicings including G, G/B, C, Em, B7, E7, Am7 and D, several of which are outside what a beginner guitar setup typically covers. Simplified strumming version: G, Em, Cadd9, D. This is the one song on this list where the guide comes with an honest caveat: the full studio chart is genuinely advanced, so the version below trades some of that harmonic color for a version you can actually play at a party.

The simplified version keeps the song's uptempo, driving feel while sticking to shapes already covered above, cycling through G, Em, Cadd9 and D for most of the song. It will not match the record note for note, but it holds the melody and the energy, which matters more for a singalong than chord for chord accuracy to the studio version.

If you already know the full chords above and want to get closer to the original, the trickiest parts are the quick chord changes in the chorus and the swung, uptempo strum underneath them, both of which respond well to slowing the whole song down with a metronome and speeding up gradually rather than trying to nail it at full tempo immediately.

Simpler Versions When a Chord Isn't Ready Yet

Not every chord above needs to be learned before you can play the song it belongs to. Several of these carols have a widely taught easier substitute built in, and using one is not cheating, it is how most players actually learn a new song for the first time.

The general rule underneath this table is that a seventh chord almost always has a plain major or minor version sitting right behind it that keeps the song recognizable, since the seventh is adding color rather than changing which chord the ear expects. Barre chords are the one category where the substitute is a genuinely different shape rather than just a simplified version of the same chord, which is why Bm gets a capo workaround rather than a plain B, since a full barre B major is not an easier version of anything.

Use the simplified column while you are first learning a song, then circle back and add the fuller chord once the song itself is comfortable. Trying to learn a new song and a new chord shape in the same practice session is usually where progress stalls on both.

Why Your Chords Sound Wrong Even When You Know the Shapes

Every song above uses chords you may already have under your fingers, and yet Christmas songs are where a lot of otherwise competent players suddenly sound rough. Here is why, one cause at a time.

The Em and Am shapes buzz on the low strings

Both chords ask your second and third fingers to sit close together on the fifth and fourth strings, and if your thumb creeps too far around the top of the neck, your fingers flatten out and mute or buzz against the string above them. Keep your thumb roughly behind your first and second fingers, pointing straight down the back of the neck, and both chords ring out cleanly.

The muted sixth string rings out on C and D

Both C and D ask you to leave the low E string out of the chord entirely, and a stray thumb or an overly wide strum catches it anyway, adding a low, dissonant note underneath an otherwise clean chord. Anchor the pad of your fretting hand thumb lightly against the top of the neck so it can damp that string if your pick brushes past it, and aim your strum to start on the fifth string for C and the fourth string for D.

Waltz time carols get strummed like pop songs

Silent Night, Away in a Manger and We Wish You a Merry Christmas are all in 3/4 time, and it is extremely easy to default to a familiar four beat strum out of habit, especially if most of your practice has been on 4/4 songs. Count out loud in threes before you start strumming any of these, and land your strum noticeably harder on beat one so your hand feels the waltz shape rather than falling back into four.

Dominant sevenths get skipped instead of learned

D7, G7 and A7 all show up more than once on this list, and it is tempting to substitute the plain major chord every time one appears rather than learning the seventh shape. That substitution is a fine stopgap while you are learning a song for the first time, but it flattens exactly the harmonic pull that makes We Wish You a Merry Christmas and Have Yourself a Merry Little Christmas feel like they are resolving somewhere, rather than just repeating.

B7 gets rushed and the stretch falls apart

B7 is the widest stretch on this list, asking your first three fingers to cover three different strings across two frets while the second and first strings stay open. Rushing straight into it from a slower chord like Em, which God Rest Ye Merry Gentlemen asks you to do, tends to make one finger land late or mute a neighboring string. Practice forming B7 on its own first, checking each string rings clearly one at a time, before you ever try changing into it from another chord at tempo.

Using a Capo to Sing These in Your Own Key

Several of these songs, Feliz Navidad in particular, are commonly played with a capo so you can use easier open chord shapes while still landing in the key the recording was made in. A capo does not change which chord shapes you play, it moves where those shapes sit on the neck, raising the pitch of every string by one fret for each fret the capo covers.

For Feliz Navidad, placing a capo on the 2nd fret and playing G, C, D and Bm shapes underneath it produces the same pitches as playing the recorded chords without a capo, but with shapes most players already know. The same trick works for any song on this list if the chords as written sit outside your comfortable singing range: find your key by ear, then check whether a capo position exists that lets you play familiar open shapes instead of the chords as originally charted. The guitar capo chart breaks down exactly which fret gets you which shape substitution.

The same idea works in reverse too. If a song feels too high to sing comfortably as written, moving the capo down is not an option since a capo only ever raises pitch, but switching to a lower key version of the same chart, if one exists, achieves the same result. Silent Night and O Come All Ye Faithful are both commonly taught in more than one key for exactly this reason, so it is worth checking whether an easier key version exists before assuming a capo is the only tool available.

A capo is also useful for something other than matching a recording: two guitars playing the same song sound noticeably richer when one player uses a capo and the other does not, since the capoed guitar's open strings ring at a different pitch even while both players use the same chord shapes. If you are playing Christmas songs with another guitarist this year, putting a capo on the 2nd or 3rd fret of one guitar while the other stays open is a simple way to thicken the sound without either of you learning anything new.

Picking the Right Key for Your Voice

Several carols above are taught in more than one key across different sources, and that is not the sources disagreeing so much as the song genuinely being singable in several places. Deck the Halls appears in both C and G. O Come All Ye Faithful is commonly taught in G, D and F. God Rest Ye Merry Gentlemen has both its traditional Em based arrangement and a simplified version built around entirely different chords.

The chords in this guide are not the one correct way to play these songs, they are a solid default that reuses a small, shared pool of shapes across as many songs as possible. If a version you find elsewhere uses different chords for the same song, that is very likely just a different key, and neither version is more correct than the other.

The practical test is simple: sing the first line of the melody on its own, without the guitar, and notice where it sits in your range. If the lowest note feels like a strain to reach or the highest note feels like a strain to hit, that song will benefit from either a capo, as covered above, or an alternate key version if one is commonly taught. Guessing at a key and forcing your voice to fit it is a common reason a song that should sound easy ends up sounding effortful.

Three Time Signatures Are Hiding in This List

Most guitar songs a beginner learns are in straightforward 4/4 time, four even beats per bar, and it is easy to assume every song works that way until a carol proves otherwise. This list actually spans three different time signatures, and knowing which one you are playing changes how you should be counting and strumming before you even touch a chord.

Jingle Bells, Deck the Halls, Santa Claus Is Coming to Town, Rockin' Around the Christmas Tree, Feliz Navidad, Have Yourself a Merry Little Christmas and All I Want for Christmas Is You are all in standard 4/4 time. Away in a Manger, Silent Night and We Wish You a Merry Christmas are in 3/4, the waltz count covered above. The First Noel stands alone on this list in 6/8, counted in two groups of three rather than three groups of two, which is why it rolls rather than marches even though six is technically double three.

If a song sounds wrong even though every chord change lands in the right place, checking whether you are counting it correctly is worth doing before you assume the problem is your fretting hand.

Chord Changes That Share a Finger

The shape of a chord is rarely the actual difficulty in these songs, since almost every shape above is a standard open chord. The difficulty is the jump between two shapes, and a few of the changes on this list are far smaller jumps than they first appear, because one finger never has to move at all.

Moving from D to D7 is the clearest example. Both chords fret the high E string at the 2nd fret with the same finger, so that finger can stay planted while your other two fingers rearrange around it, which turns what looks like a full chord change into a two finger adjustment. The same is true moving from C to Am, since both chords fret the B string at the 1st fret with your first finger, making that pairing, which shows up back to back in Have Yourself a Merry Little Christmas, easier than it looks on paper.

Em to B7, covered above in God Rest Ye Merry Gentlemen, works the same way through the second fret of the A string. None of these tricks make a new chord easier to form in isolation, but they make the specific transition between two particular chords considerably smoother, and it is worth noticing which pairs in a song you are learning share a finger like this before you assume every chord change requires moving your whole hand.

Getting Your Chord Changes Up to Caroling Speed

Knowing a shape and being able to switch into it in half a second while everyone around you keeps singing are two different skills, and the second one is what actually makes these songs playable in a group rather than just alone in your room. The fastest changes on this list, We Wish You a Merry Christmas and the Dm to G7 move in Have Yourself a Merry Little Christmas, both reward the same practice approach.

Isolate the two chords that give you the most trouble and change back and forth between just those two, slowly, with a metronome, long before you try to play the whole song at tempo. Once that specific change is smooth, drop it back into the full song and the rest tends to fall into place, since the surrounding chords you already know are rarely the actual bottleneck. A metronome for rhythm guitar is worth setting up for this rather than guessing at your own tempo.

Start well under the recorded tempo, slow enough that every change feels easy rather than merely possible, and raise the metronome only once a chord change feels boring at the current speed rather than the moment it stops feeling wrong. It is tempting to judge your progress by how close you sound to the record, but a change that is technically correct at a rushed tempo tends to fall apart the first time you also try to sing, whereas a change drilled slowly and correctly holds up under pressure far more reliably.

Playing These Around the Tree, Not Just Alone

A song that sounds great practiced solo can fall apart the moment other people start singing along, mostly because a group singalong is less forgiving of hesitation than practicing by yourself. If you are playing for family rather than performing, simpler is almost always the better call.

Where a song offers a genuinely easier version, the two chord Jingle Bells, the no barre First Noel, the G major Santa Claus Is Coming to Town, lean toward it in a group setting rather than the fuller arrangement, since a confident simple version carries a room better than a hesitant complicated one. Keep your strum steady and a little quieter than you would practicing alone, so your guitar supports the singing rather than competing with it, and do not be afraid to just repeat the same chord loop if people want to sing another verse.

Carols like Silent Night, Away in a Manger and O Come All Ye Faithful tend to work especially well for this, since a room full of people already half remembers the words and mostly needs a steady chord underneath to follow. Faster, more modern songs like Rockin' Around the Christmas Tree and All I Want for Christmas Is You are harder to carry solo in a group setting, since the energy of the recorded version comes partly from a full band, so treat those two as fun additions once the calmer carols are solid rather than the first songs you reach for around a tree full of relatives.

A One Week Practice Plan

If you are working toward a specific date rather than learning at a relaxed pace, here is a way to spread these eleven songs across a week without overloading any single day.

Spend the first two days on the toolkit chords themselves, G, C, D, Em and Am, until switching between any two of them is instant rather than something you have to think through. Day three, add Jingle Bells, Deck the Halls and Silent Night, all of which use only chords you already have. Day four, add Away in a Manger and introduce D7, then use the no barre substitute to get through The First Noel as well.

Day five, add We Wish You a Merry Christmas and O Come All Ye Faithful, bringing in A7 and A major and the faster harmonic movement covered above. Day six, tackle Santa Claus Is Coming to Town and Rockin' Around the Christmas Tree together, since both share a similar swung or syncopated feel and reinforce each other. Day seven, finish with Feliz Navidad, Have Yourself a Merry Little Christmas and the simplified All I Want for Christmas Is You, using whichever spare time you have left to go back and smooth out whichever song from earlier in the week is still shaky, since a familiar song revisited briefly improves faster than a new one crammed in.

God Rest Ye Merry Gentlemen and its B7 stretch are worth treating as a standalone project rather than squeezing into the schedule above. Once the rest of the list feels settled, give that one carol its own few days, using the simplified Am, E, F, Dm, C, G version first and only adding the full Em, C, B7 progression once that four finger shape is comfortable on its own.

Frequently Asked Questions

What is the easiest Christmas song to play on guitar?

Jingle Bells, using just G, C and D with no capo and no barre chords required. An even simpler two chord version exists using C and G7 for absolute beginners still building up their chord vocabulary.

Do I need a capo to play Christmas songs on guitar?

No song on this list strictly requires one. A capo becomes useful when you want to match a specific recorded key, most commonly with Feliz Navidad, while still playing familiar open chord shapes.

Can I play these Christmas songs without knowing any barre chords?

Yes, for most of them. The First Noel and Feliz Navidad are the two songs above that call for Bm in their fuller arrangements, and both have widely taught no barre substitutes if that shape is not comfortable yet.

Why do Christmas carols feel harder to strum than pop songs I already know?

Three of these carols, Away in a Manger, Silent Night and We Wish You a Merry Christmas, are in 3/4 waltz time rather than the 4/4 most modern songs use, and The First Noel is in 6/8. Strumming any of them with a default four beat feel is the most common reason they sound off even when the chords themselves are correct.

Should I strum or fingerpick these songs?

Either works, but the two slower carols above, Silent Night and The First Noel, generally suit fingerpicking better, while the uptempo pop songs like Rockin' Around the Christmas Tree and All I Want for Christmas Is You want a driving strum to carry their energy.

What chords should I learn first if I only have a week?

G, C, D, Em and Am cover the majority of these songs on their own. Adding D7, G7 and A7 on top of that toolkit unlocks every song on this list.

Is the simplified All I Want for Christmas Is You arrangement going to sound like the record?

Not exactly. The original recording uses jazz voicings well beyond a typical open chord songbook, so the G, Em, Cadd9, D version here trades some of that color for something playable at a family gathering, while keeping the melody and energy intact.

Why is God Rest Ye Merry Gentlemen harder than the other carols on this list?

It is the only minor key carol here, and its traditional arrangement calls for B7, a four finger stretch that is the widest chord on this list. A simplified version using Am, E, F, Dm, C and G exists for exactly this reason, and it is worth using while B7 is still new.

Do I need to learn every chord exactly as written, or can I substitute easier ones?

Substituting is normal and not a shortcut you need to grow out of quickly. A plain major chord in place of its seventh, or a capo workaround in place of a barre chord, keeps a song recognizable while you build up to the fuller version, and plenty of players never bother going further than that.