Note Frequency Reference
Frequency in Hz for every note and octave, in standard equal temperament.
Last updated
| Note | Frequency (Hz) |
|---|
How to find a note’s frequency
- Find the note and octave in the chart.
- Change the A4 reference pitch (440 Hz by default) to see every frequency shift with it.
About this reference
Standard 12-tone equal temperament splits every octave into 12 equal ratios, so each semitone's frequency is the one before it times 2^(1/12) — that's why frequency exactly doubles one octave up (A5 is exactly 2× A4) but doesn't increase by an equal number of Hz per semitone. A4 = 440 Hz is the modern concert-pitch standard, but some orchestras and eras tune slightly sharp or flat (442 Hz is common in parts of Europe) — adjust the reference pitch above to see every other note shift with it.
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Questions about note frequencies
What frequency is middle C?
About 261.63 Hz (C4), with A4 tuned to 440 Hz.
Why is A tuned to 440 Hz?
It’s the modern international concert pitch standard. Some orchestras tune slightly higher, such as 442 Hz.
How do frequencies change by octave?
They double: A4 is 440 Hz, A5 880 Hz and A3 220 Hz. Each semitone multiplies the frequency by 2^(1/12), about 1.0595.
What is 432 Hz tuning?
Tuning A4 to 432 Hz instead of 440. Set the reference pitch to 432 to see the whole chart change.