The Chrome extension charts a song as it goes by. The iPhone app reads the whole song first — every bar, the key, the tempo, the meter, the downbeats — then plays it back with the chart already on the screen. From the mic, from a web player, or from an audio file. Same math, same privacy, a lot more hindsight.
Everything the extension does, plus the things a phone makes possible: a mic, a file, a real guitar in your hands, and a screen you can prop on a stand.
That's a big claim, so here's the list. Four modes: a single-note needle, a strum mode that reads all six strings from one strum, a strobe, and 3D — eight ways to watch pitch that nobody has shipped before. Equal, sweetened, and just intonation tuned to the key of the last song you charted, so open chords ring pure. Capo-aware, so you tune with it clamped and it targets the fretted pitches. Thirty-plus tunings from standard through DADGAD, baritone, 7-string, 5-string bass, mandolin, banjo, cello, and dobro, plus your own custom tunings. Then the setup tools nobody ships: a guided intonation check (open vs. 12th fret, with a saddle verdict), string freshness that hears when a set has gone dead, a stretch-tuning pass for new strings, a drone to tune by ear, and octave stretch curves for guitar and piano.
The decoder reads the entire song before it commits to a chart: key, a beat grid that never drifts, bar lines, and the chords on every beat. Then the chart plays along, one bar highlighted at a time. No guessing at the edge of the audio. Tap any bar to loop it in the player.
Listen charts what your band or your guitar is playing right now. Browser charts a YouTube video straight from the player's audio, lossless, ahead of time. File charts a whole recording before you press play. Share a link from any app and Chartless picks it up.
Meter detected from the audio, including compound time. Wrong? Pick it. Downbeat off? Tap the 1 while it plays. Tempo locked on the wrong pulse? Tap along and the decoder re-reads the song around your tap. Tuned on a benchmark of real worship recordings.
Pick your instrument and tuning in Settings and every chord diagram is drawn for it. Standard shapes stay hand-made. Drop D, drop C, and 7-string keep the shapes you know with the retuned strings worked out. Open G and open D get barre shapes. DADGAD gets the drone voicings you'd actually play. Left-handed, too.
Song in D♭ on a DADGAD guitar? "Capo 6, play G shapes," with the key you'd play in listed next to every fret. Pick it and the names, the diagrams, and the nut label all follow. Recommendations only until you say so.
Build a progression or import it from any charted song, set the tempo (or tap it), pick a time signature, and loop it. Voice-led chords played by a synth pad or any of 120 sampled General MIDI instruments, an arpeggiator, a click, and a fingering diagram that follows your instrument.
Chord as big as the phone, the next one underneath, beat dots, key and tempo, and your own brightness control so a dark stage stays dark. Turn the phone sideways and it opens by itself.
Every chart becomes a chord sheet you can clean up: remove a mistaken chord, fix a bar, then export a PDF laid out like the extension's. Or send it to the practice room, or look the song up on Ultimate Guitar, SongSelect, or Google.
Playing by feel? In mic mode the app offers where to go next from the chord you're on: safe, lift, or shade, with the why behind each. Nashville numbers as an instrument, so the whole chart reads 1 · 4 · 5.
In the browser, one tap reads the page's own labels and a few audio tells and gives you a verdict with the reasons. Uploaded before 2023? That's a hard no, and it says so.
Classic signal processing on the phone. Audio is never uploaded, never recorded, never used to train anything. Songs you chart stay on your device.
Here's a secret every guitar tech knows and almost no tuner will tell you: a guitar tuned dead-on to the needle is not in tune with itself. The math that lets one guitar play in every key asks every note to give a little. So your open G rings, your open D shimmers a hair, and you reach for the tuner again without knowing why.
Sweetened is one tap. Chartless nudges each string by an amount you'd never hear on its own, and the chords you actually play stop fighting and start singing. Open chords bloom. Barre chords sit still. The wobble you learned to live with is just gone.
Flip on Just and it goes a step further: it tunes to the key of the last song you charted, so the chords in that song ring pure. Change songs, tune again, twelve seconds. The kind of thing you used to need a session player's ear for, now living in your pocket.
It's not magic. It's arithmetic, done for you, and it sounds like magic.
They share one engine and one privacy stance. They differ in when they chart and what they can reach. The extension is done and yours forever for one price. The app is a subscription, because it keeps growing.
| Chrome extension | iPhone app | |
|---|---|---|
| When it charts | Live, as the song plays, with a short lookahead | The whole song first, then plays it back with the chart already drawn (mic stays live) |
| What it can hear | Any browser tab, or your mic | Your mic, a web player inside the app, or any audio file on the phone |
| Bars and meter | Beat pulse and measure count | Bar-by-bar chart, 4/4 · 3/4 · 6/8 detected, Tap the 1, tap-tempo hint, loop any bars |
| Chord diagrams | Guitar, uke, bass, piano in standard tuning | Nine instruments, thirty-plus tunings, drone and barre styles, left-handed |
| Capo advisor | Standard tuning | Knows your tuning; shows the key you'd play in at every fret |
| Tuner | Basic single-note tuner | The full suite: strum, strobe, temperaments, capo-aware, custom tunings, intonation check, string freshness, stretch, drone |
| Practice room | — | Loop any progression on 120 sampled instruments, arpeggiator, click |
| Export | Chord sheet PDF | Editable chord sheet, PDF, share as text, send to practice |
| Stage view | Full-screen chord | Full-screen chord, auto in landscape, brightness slider |
| Price | Free, Pro for one small price, yours for good | Subscription, try it free first. Details at launch. |
One email when it launches, one when the free trial opens up early if you asked for it. That's the whole list. No newsletter.
Your address is stored for this one purpose and deleted after the launch mail goes out. Or just email [email protected] and say "iPhone".The app analyzes audio on the phone with classic signal processing and throws it away. No servers, no models, no analytics. The one exception is the AI-likelihood check in the browser, which reads the page you're already looking at. Read the privacy policy.