EDO Calculator

Free tool to calculate equal divisions of the octave (EDO, TET) in Hz and cents, with .scl export. No sign-up

Type the number of divisions, or load a preset like 19-EDO, 24-EDO or 31-EDO.
Leave the period at 2/1 for the octave, or change it, for example 3/1 for Bohlen-Pierce.
Pick a tonic and a reference frequency (A4 = 440 Hz by default).
Read the step size, the constant and the table with Hz, cents and the offset from 12-TET.
Play a step or the whole scale, or hold a drone on the tonic.
Download an .scl file for synths and samplers, save a CSV, or copy the scale as text.

The period is the interval that gets divided: 2/1 is the octave, 3/1 the tritave. Write it as a ratio (3/1), a whole number (2) or cents with a decimal point (1901.955), then press Enter. “vs 12-TET” is the distance in cents from the nearest equal-tempered note; more than 10 cents is highlighted.

Nothing is saved or uploaded: everything stays in your browser. Download or copy your scale before closing the page. The tonic is tuned in 12-tone equal temperament from the A4 reference, and .scl files store the steps only, not the tonic.

How do you calculate the frequencies of an equal temperament with a number of steps other than 12?

To divide the octave into n equal steps, multiply the frequency by the n-th root of 2 at every step: each step is 1200 ÷ n cents. For 12 steps the constant is 1.05946 (100 cents), for 24 steps it is 1.02930 (50 cents), and for 19 steps it is 1.03715 (63.16 cents). This free calculator gives you the constant, the frequency and cents of every step, how far each one is from 12-TET, and an .scl file for your synth or sampler.

What is an EDO?

EDO stands for equal division of the octave, and TET is the older name for the same idea. The piano uses 12 equal steps, but you can cut the octave into any number: 24 gives quarter tones, and 19, 31 or 53 are popular because their steps come close to pure intervals like 5/4 and 3/2. Every step has the same size in cents, so music in an EDO can be moved to any starting note without changing its tuning, which a just intonation scale cannot do. A cent is one hundredth of a 12-TET semitone.

Made by Luca Martone, sound designer and live sound engineer based in Turin.