There are two guarantees in life: you will one day stand in a room full of people mumbling this tune slightly out of tune, and you will secretly be judged if you cannot play it. So here it is — Happy Birthday on guitar, done properly, as a full chord melody where the melody and the chords live in the same part and you never once have to yell "everybody sing along!"
This clip is MelodyChords number 13: a compact fingerstyle arrangement of Happy Birthday for solo guitar. It starts in the comfy key of C major and then, because I like to make things interesting, shifts up to Ab major — a tidy little study in transposing a song so you can match whichever brave soul is doing the singing.
How this chord melody works (and why the key change is the point)
A MelodyChords arrangement puts the tune on top and tucks the harmony underneath, so one guitar sounds like a whole tiny band. The trick is keeping the melody note as the highest voice while the chord fingers do the quiet supporting work below it — your thumb and fingers split the job so the "Happy Birth-DAY to you" line always sings out clearly over the chords.
Then comes the useful bit: I play the whole thing again in Ab major. That is not showing off (okay, a little) — it is a transposition study. Everything drops a major third, the shapes and fingerings change, but the intervals stay identical, because a melody does not care what fret it starts on. The concrete takeaway: learn one tune in two keys and you suddenly understand your fretboard as a system of movable shapes, not a pile of memorised dots — and you can drop Happy Birthday into whatever key keeps grandpa in range.
Play it once and you are the hero of every birthday until the end of time; play it in the wrong key and grandpa strains a vocal cord. Grab the PDF, pick your key wisely, and if you want the Guitar Pro file and the original videos, they live on my Patreon.