Note Frequency Calculator
Convert any musical note to its frequency in Hz, or enter a frequency to find its closest note. Full piano chart from C0 to C8.
Note to Frequency
Frequency to Note
Common Reference Frequencies
Full Piano Frequency Table
All 88 piano keys plus beyond. Reference tuning: A4 = 440 Hz. Click any note to see its frequency in the converter above.
| Oct | C | C# | D | D# | E | F | F# | G | G# | A | A# | B |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| 7 | ||||||||||||
| 8 | - | - | - | - | - | - | - | - | - | - | - |
All values in Hz. Standard equal temperament, A4 = 440 Hz.
Why Note Frequencies Matter in Music Production
EQ and Mixing
Knowing a note's fundamental frequency helps you cut or boost exactly where an instrument lives. If your bassline is in C, the fundamental of C2 is 65.41 Hz. Use a high-pass filter above that to remove subsonic mud, or notch out 65 Hz on competing elements to make space.
Tuning 808s and Samples
An 808 kick is a pitched sound. If your track is in the key of G and your 808 defaults to C, it will clash. Find the frequency of C (your 808's root) and the frequency of G (your target), then pitch-shift by the difference in semitones to lock them together.
Sidechain Filter Tuning
Dynamic EQ sidechains work best when you tune the detector filter to the kick's fundamental. If your kick punches hardest at 80 Hz (approximately E2), set your sidechain high-pass at 60-70 Hz so the compressor fires on the kick's main energy, not room rumble.
Synthesizer Oscillator Pitch
When layering synths with samples, use note frequencies to verify pitch alignment. A sample pitched to 440 Hz is A4. If your synth oscillator shows 220 Hz in its frequency display, that is A3 (one octave lower). Matching note frequencies ensures layers stay in tune.
The Note Frequency Formula
Every note frequency is derived from A4 = 440 Hz using the formula:
Where n is the MIDI note number (A4 = 69, middle C = 60). Each octave up doubles the frequency, each octave down halves it. Moving one semitone up multiplies by the 12th root of 2 (approximately 1.0595). Moving one semitone down divides by that same factor.
Frequently Asked Questions
What frequency is the note A4?
A4 (the A above middle C) is exactly 440 Hz. This is the international tuning standard (ISO 16) used by orchestras, DAWs, hardware synths, and electronic tuners worldwide. All other notes are calculated from this reference.
What frequency is middle C?
Middle C (C4) is 261.63 Hz. It is MIDI note 60 and sits in the center of a standard 88-key piano. It is one of the most important reference points in Western music theory and notation.
How do I convert a note to its frequency?
Use the formula: frequency = 440 x 2^((MIDI - 69) / 12). For example, A5 is MIDI 81, so: 440 x 2^((81-69)/12) = 440 x 2^1 = 880 Hz. Or just use the Note to Frequency converter at the top of this page.
Why do producers care about note frequencies?
Producers use note frequencies for EQ precision (cut at a note's fundamental to reduce clashing), 808 and bass tuning (pitch an 808 to match the track key), sidechain filter tuning, and synth oscillator alignment when layering with samples.