The notation it reads

Each part is one line of text. A bar line | separates the bars, and so does a line break: a part may be typed one bar to a line, and a bar line at the end of a line counts once with the break. Words are separated by spaces, and every word is either a rhythm word or a note. Capitals do not matter.

Rhythm words

WordMeans
taa quarter note
ti-titwo eighth notes
tione eighth note
tika-tikafour sixteenth notes
tikatwo sixteenth notes
ti-tikaan eighth and two sixteenths
tika-titwo sixteenths and an eighth
tim-kaa dotted eighth and a sixteenth
syn-co-paan eighth, a quarter and an eighth
ti-ti-tithree eighth notes (a beat of 6/8)
ta-ia dotted quarter note (a beat of 6/8)
ta-aa half note
ta-a-aa dotted half note
ta-a-a-aa whole note
resta quarter rest

Notes with a pitch or a length

A note word is what it is, a slash, and its length: C5/4 is a quarter note C5, F#4/8 an eighth note F sharp, Bb5/2 a half note B flat, x/8 an eighth note with no pitch and r/2 a half rest. Lengths are 1 (whole), 2 (half), 4 (quarter), 8 (eighth) and 16 (sixteenth), written without a leading zero; a full stop after the length dots it (G4/4.). Pitches run from C4 to C6, with # for sharp and b for flat.

Ties

A ~ at the end of a word ties its last note to the next note of the same part, across a bar line if need be: ta ta ta ta~ | ta ta-a ta. A tie joins two notes of the same pitch; a rest cannot be tied.

What happens to a word that does not read

Nothing is guessed. The part stays as it was and every word that did not read is listed with its bar and place. For the line ta tii ta | C4 x/3 ta | ta ta ta ta~ the maker says:

A bar that does not add up, a tie to nothing and a bells note with no pitch are listed the same way under the grid.

The rules, in the order they run

  1. Bars add up exactly. A bar of 2/4 holds 2 quarter notes, 3/4 holds 3, 4/4 holds 4, and 6/8 holds 6 eighths. Lengths are counted in sixteenths. A bar that is short or long is marked with how much, and the board does not play or export until every bar adds up. The one fix offered is Fill with rests, and only when you press it.
  2. Ties and pitches are checked. A tie needs a next note of the same pitch; a bells part needs a pitch on every note, from C4 to C6. Rhythm parts keep any pitch they were given but do not play it.
  3. Keep bars full (a switch, on unless you turn it off). In the grid, a longer note takes its time from the notes after it in the same bar, and what is left of a note it cuts is written as the shorter values that remain; a shorter note leaves a rest after it; Split puts two notes in the place of one; Delete leaves a rest. If there is no room after a note, the change is refused and nothing moves. With the switch off, an edit changes only the note.
  4. Drawing. Eighths and sixteenths are beamed within one beat (a quarter note in simple time, a dotted quarter in 6/8), so eighths come in pairs in 2/4, 3/4 and 4/4, as in most classroom material; a rest breaks a beam. A sharp or flat holds to the end of its bar, so a later natural note shows a natural sign. Notes of every part that start together line up. Up to 16 bars and 4 parts.
  5. Words under the notes. Rhythm syllables name each note by its length (ta, ti, ta-a, ta-a-a, ta-a-a-a, ta-i for a dotted quarter, tim for a dotted eighth; sixteenths are ti on an eighth line and ka between). Counting names each note by where it starts: 1, e, &, a in simple time, and 1 to 6 with & between in 6/8. A rest is “rest” or its count in brackets; the held end of a tie is a tilde (~), the same mark as in the text notation.
  6. Playback. The count-in plays a click on every beat for 1 or 2 bars, the first beat of the bar higher. Then the board plays as many times as you set, and again from the top while Loop is on, with no second count-in. A tempo change starts at the next bar line, or at the one after when the next is less than 0.25 seconds away.
  7. Video and charts. The video is the same performance at the board's tempo with no loop: a 3-second title card, the count-in, every pass, and 1 second for the last note to ring. The charts print the board as written.

Worked example: 3 bars of 4/4 at 120

The line ta ti-ti rest tika-tika | ta-a ta~ | ta ta-a-a at 120 beats a minute with a 1-bar count-in. A beat lasts 0.5 seconds, a sixteenth 0.125 seconds, so the count-in fills the first 2 seconds. Each note starts at its bar's start plus its place in sixteenths times 0.125, and rings until the next note (the tied quarter in bar 2 rings on through the first beat of bar 3, which does not sound again).

BarSyllableStarts at (seconds)Rings for (seconds)
1ta2.0000.500
1ti2.5000.250
1ti2.7500.250
1ti3.5000.125
1ka3.6250.125
1ti3.7500.125
1ka3.8750.125
2ta-a4.0001.000
2ta5.0001.000
3ta-a-a6.5001.500

The quarter rest in bar 1 and the held end of the tie in bar 3 make no sound, so they are not in the table.

The colour convention, and how to change it

The starting convention is red C, orange D, yellow E, green F, teal G, purple A, pink B: one colour a letter, a common choice for colour-coded tubes and bells. Open Settings and parts and choose another colour for any letter to match the set in your room; the chart, the coloured notes and the video follow it, and it is saved with the board. A sharp or flat takes its letter's colour and is printed with its sign, and every circle carries its letter in black or white, whichever reads better on that colour.

How the marker stays in time

Every sound is scheduled on the browser's audio clock with its exact start time, worked out as the bar's start plus its place in sixteenths times the length of a sixteenth, so nothing is added up note by note and nothing drifts. A short timer wakes every 25 milliseconds and schedules whatever starts in the next 0.25 seconds (2 seconds while the tab is in the background, when browsers slow timers); the timer decides only when to look ahead, never when a note sounds. The marker reads the same audio clock on every screen refresh, less the output delay the browser reports, so it sits on the note you hear. Everything is scheduled on the audio clock, and in our tests the drift stays under 20 milliseconds over 16 bars at 200 beats a minute.

Sound starts only when you press Play: the browser's sound is switched on by that press, and nothing plays when the page opens.

Video formats by browser

BrowserWhat it makes
Chrome and Edge on a computer, Android ChromeMP4 (H.264 video, AAC or Opus sound), made in the background faster than it plays
Safari 26 on a Mac, iPhone or iPadMP4 (H.264 video) made in the background where its encoders offer sound as well; otherwise a recording made while the video plays once
FirefoxMP4 where the system offers H.264 encoding; otherwise WebM, recorded while the video plays once
Older Safari and older iPads without WebCodecsA recording made while the video plays once (MP4 or WebM, as the browser's recorder makes), or, where even that is missing, no video: the page says so, and the PNG chart and printing still work

The maker checks the browser before it starts and says which file it will make. Videos are 1920 by 1080 (landscape) or 1080 by 1920 (portrait), at 24 or 30 frames a second. They are made in chunks with a progress bar and a Cancel button; a cancelled video leaves no file behind. The finished file stays in this browser until you save it.

What it is not

Clapchart is not affiliated with any instrument maker, publisher or music exam board.