Note frequency chart and frequency-to-note converter
This note frequency chart lists the frequency in hertz of every note from C0 to B8 — the full range of a piano and beyond — and works the other way too: type any frequency and it tells you the nearest note and how many cents sharp or flat it is. It covers standard concert pitch (A4 = 440 Hz), the popular 432 Hz tuning, baroque pitch (415 Hz), orchestral 442–443 Hz or any reference you type.
Musicians use it to tune instruments by ear or with a meter, producers to set filters and synth oscillators on a note, sound engineers to find which note a room resonance or feedback whistle sits on, and students to see how the octave doubling and the twelfth root of two actually work. Click any cell to hear a short tone, or open the note in the tone generator to hold it, sweep it or save it as a WAV file.
How to use the Note Frequency Chart
- Pick a reference pitch: leave A4 = 440 Hz, press 432, 442, 443 or 415, or type your own.
- To convert a note, type it with its octave in Note name (A4, C#5, Bb3) or enter a MIDI note number; the frequency appears at once.
- To convert a frequency, type it in Frequency; the result shows the nearest note and the cents between them.
- Read the frequency of any note in the chart: rows are note names, columns are octaves. Click a cell to hear it and load it into the converter.
- Use Print chart for a paper copy or Download CSV for a spreadsheet; both follow the reference pitch you chose.
Note Frequency Chart features
Any reference pitch
One-click presets for 440, 432, 442, 443 and 415 Hz, or any value from 100 to 1,000 Hz; the chart and the converter update together.
Three-way converter
Note name ↔ MIDI number ↔ frequency, accepting sharps, flats, double accidentals and octaves −1 to 9.
Nearest note and cents
Any frequency is matched to the closest equal-tempered note, with the deviation to a tenth of a cent.
Extra numbers
Period, wavelength in air, the same note at standard pitch and the octaves above and below.
Hear it
A one-second sine tone plays when you click a note (switch it off with the checkbox); the tone generator link holds the note as long as you like.
Print and CSV
A clean black-on-white printed chart and a 108-row CSV with MIDI numbers and wavelengths.
The formula: twelve equal semitones per octave
In twelve-tone equal temperament every semitone multiplies the frequency by the same ratio, the twelfth root of two (about 1.059463), so twelve semitones exactly double it. With MIDI numbering, where A4 is note 69 and middle C (C4) is note 60, f = A4 × 2(n − 69) / 12. At A4 = 440 Hz, C4 is 440 × 2−9/12 = 261.63 Hz; Bb3, eleven semitones below A4, is 233.08 Hz.
Going the other way, n = 69 + 12 × log2(f ÷ A4). The whole number nearest to n is the note, and the remainder times 100 is the deviation in cents (100 cents = one semitone). A 1,000 Hz test tone, for example, gives n = 83.21: the note B5 (987.77 Hz) plus 21.3 cents. Most listeners notice a difference of about 5–10 cents between two notes played one after the other.
Common reference pitches
Claims that 432 Hz is more “natural” or healing are not supported by evidence; it is simply a different reference, and a piece played at 432 Hz sounds about a third of a semitone lower.
| A4 | Where it is used | C4 (middle C) |
|---|---|---|
| 440 Hz | International standard concert pitch (ISO 16:1975); most pianos, guitars, tuners and software | 261.63 Hz |
| 442–443 Hz | Many European orchestras tune slightly higher for a brighter sound | 262.82–263.41 Hz |
| 432 Hz | Alternative tuning popular online; about 31.8 cents below 440 | 256.87 Hz |
| 415 Hz | Baroque pitch for period instruments, about a semitone below 440 | 246.76 Hz |
Reading the chart and octave numbers
Octave numbers follow scientific pitch notation: each octave starts on C, so B3 is followed by C4. Middle C is C4 (MIDI 60). Some software and keyboards label middle C as C3 or C5 — check the MIDI number if a chart elsewhere seems one octave off. Shaded rows are the black keys of a piano; the chart shows them as sharps, flats or both. An 88-key piano runs from A0 (27.50 Hz) to C8 (4,186.01 Hz).
Wavelengths use 343 m/s, the speed of sound in dry air at 20 °C, so they are approximate for other temperatures. For chords and scales built on these notes, see the piano chord finder; to check what an instrument is actually playing, the online tuner listens through your microphone.
Note Frequency Chart FAQ
What frequency is middle C?
Middle C (C4) is 261.63 Hz at standard pitch A4 = 440 Hz, and 256.87 Hz if A4 is tuned to 432 Hz.
How do I convert a frequency to a note?
Type the frequency in the Frequency box. The calculator works out n = 69 + 12 × log₂(f ÷ A4), rounds it to the nearest note and shows the remaining cents, so 450 Hz reads as A4 +38.9 cents.
What is the note frequency chart for 432 Hz?
Press the 432 preset. Every note is then about 31.8 cents lower than at 440 Hz: A4 = 432 Hz, C4 = 256.87 Hz, E4 = 323.63 Hz. Print or download it as CSV.
Why does the chart start at C0?
C0 (16.35 Hz) is near the lower limit of human pitch perception. The converter still accepts MIDI notes down to C−1 (8.18 Hz) and up to G9 (12,543.85 Hz) at standard pitch.
Is the tuning equal temperament or just intonation?
Equal temperament, the tuning used by pianos, fretted instruments and almost all digital instruments. Just intonation and historical temperaments shift some notes by a few cents and are not shown.
Can I hear the notes?
Yes — click any chart cell or press Play note for a one-second sine tone. Keep your volume low at first. For a continuous tone use Open in tone generator.