What Is ChordPro, and Why Your Next Chart Should Be One

If you've ever opened a .pro, .cho, or .crd file and found something that looks like this, you've already met ChordPro:

That's the whole format. No proprietary app required to read it, no special software to write it — just lyrics, with the chord that goes over each word dropped in as a bracketed tag right where it's played. Section labels like {c:Verse} mark the parts of the song, and a handful of other tags ({title:}, {subtitle:}, {key:}, and so on) carry the metadata. That's genuinely most of what there is to know.

Why musicians use a plain-text format in 2026

ChordPro has been around since the 1990s, which sounds like a strange selling point for a format — until you notice what it bought everyone who adopted it. Because a ChordPro file is just text, it isn't tied to the app that created it. The same .pro file opens in the ChordPro reference software, in songbook and lyrics-display apps like OnSong, Songbook, and MobileSheets, and in plenty of others across iOS, Android, and desktop. Write it once, and it's readable everywhere, forever — no export lock-in, no "this only works in our app."

That's also why it holds up for something as unglamorous as long-term storage. A folder of .pro files is still just a folder of text files in twenty years. Try that with a proprietary chart format from an app that's since shut down.

The part nobody enjoys: writing one from scratch

Here's the catch. A blank .pro file doesn't write itself. Someone still has to listen to the recording, figure out every chord change, and place each one in exactly the right spot in the lyrics — which is the same slow, ear-heavy work whether you're typing brackets into a text file or filling out a chart by hand on paper. For a three-minute song, that's easily twenty or thirty minutes of stopping, rewinding, and second-guessing a chord before you've even gotten to the parts you actually wanted to work on — playing it, arranging it, teaching it to a band.

Generating the file instead of typing it

This is the actual gap ChordPro Studio fills. Upload an MP3 or WAV of the song, and it transcribes the lyrics, detects the chords, and places them inline — the same bracket-and-lyric structure shown above — automatically. What comes out is a real, working ChordPro file, not a proprietary format you'd need to convert later.

Worth being direct about one thing: this is a first draft, not a finished chart. Audio-to-chord detection is genuinely hard, especially on a dense mix, so treat what comes back as a strong starting point to fine-tune in the built-in editor — not something to trust blindly. Even so, correcting a handful of chords in an already-placed draft is a very different job than building the whole thing from a blank file and a pair of headphones.

Try it on a song you already have

If you're already working in ChordPro — or you just inherited a .pro file and want to understand what you're looking at — the fastest way to see the difference is to hand ChordPro Studio a recording, or a chord-sheet PDF you already have, and watch it come back as a chart you can open in the same tools you already use.