Note Frequency Chart

Every musical pitch is a frequency, a number of vibrations per second. Tuning an instrument, setting an equaliser, choosing a bass-trap size or writing a synth patch needs the numbers. This chart lists the frequency of every note from C0 to B8, with its MIDI number and the wavelength of the sound in air, and adds a table of note lengths for any tempo.

The rule behind the numbers

Western music uses twelve-tone equal temperament: an octave doubles the frequency, and it is divided into twelve equal steps called semitones. Each step multiplies the frequency by the twelfth root of two, 1.059463. If A4 is 440 Hz, the note n semitones above is 440 × 2^(n/12). Middle C is nine semitones below A4, so it is 440 × 2^(-9/12) = 261.63 Hz. Because equal temperament compromises every interval a little, a string tuned by ear in a pure scale will differ by some cents.

A worked example

Press Sample, which sets A4 to 440 Hz, shows octave 4, sharp names and a tempo of 120 BPM. The C4 row reads MIDI 60, 261.63 Hz and 1.313 m: the wavelength is 343.4 divided by 261.63. A4 is 440.00 Hz and 0.780 m. Choose the A4 = 415 button and A4 becomes 415.00 Hz, which is within 0.3 Hz of G sharp 4 at modern pitch, 415.30 Hz. That is why Baroque pitch, A = 415, is described as a semitone below modern pitch.

Choosing a reference pitch

Most modern ensembles tune to A = 440 Hz. Many orchestras in Europe use 442 or 443 Hz for a brighter sound, and some use 444. Baroque ensembles often play at A = 415 Hz, a semitone below, and A = 432 Hz is sometimes used as an alternative tuning. The chart recalculates all 108 rows at the reference you enter, so you can compare. A keyboard or fixed instrument must be tuned to one reference, so ask before playing with one.

Wavelength and why it matters

Wavelength is the speed of sound divided by frequency. At 20 °C the speed is about 343.4 m/s, so a 55 Hz note is about 6.2 metres long and a 1,000 Hz note is 34 cm. Long bass wavelengths explain room modes and why small speakers lose the low notes, while short ones are absorbed by thin panels. The values change with temperature, since sound is slightly faster in warm air.

Note lengths at a tempo

The second table turns the tempo into time. At 120 BPM a quarter note lasts 500.0 ms, a dotted quarter 750.0 ms and a quarter-note triplet 333.3 ms. These are the numbers that delay, reverb pre-delay and LFO settings use to stay in time with a track. The table lists six note values in straight, dotted and triplet form.

Using the table

Pick a single octave from the list or show all nine. Copy as CSV takes all rows to a spreadsheet, with columns for note, MIDI number, frequency and wavelength. The names toggle swaps between sharps and flats. Frequencies are rounded to 0.01 Hz on screen and 0.001 Hz in the CSV.

Limits

The chart is equal temperament only; it does not include just intonation, meantone or other historical temperaments. Notes beyond B8 and below C0 are not listed. The wavelength assumes dry air at 20 °C.

Related tools

• Tone Generator plays any frequency in the table.
• Online Tuner compares a played note with its target.
• Delay Time Calculator expands the note-length table into delay and reverb times.
• Room Modes Calculator uses wavelength to find the resonances of a room.