Frequency to Note Converter
Type a frequency in hertz to see the nearest musical note, and how many cents sharp or flat it is. Or pick a note to get its frequency. A Hz to note converter and note to frequency calculator in one, with A4 = 440, 432 or 442 Hz, and a play button to hear both.
− and + move 1 Hz; hold Shift for 0.1 Hz. Arrow keys work in the box too.
F5
700 Hz is F5, 4 cents sharp (A4 = 440)
Drag the needle to change the frequency.
Works on numbers you type, from 16 to 8,000 Hz: it doesn’t listen to the microphone. Drag the needle or press − and + to move the frequency, and tap any number in the table to see that note.
Frequencies of every note
Every note from C0 to B8 in hertz, at the tuning chosen above, rounded to two decimals. The shaded notes are the 88 keys of a piano; A4 and middle C (C4) are in bold.
| Note | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|---|
| C | |||||||||
| C♯ / D♭ | |||||||||
| D | |||||||||
| D♯ / E♭ | |||||||||
| E | |||||||||
| F | |||||||||
| F♯ / G♭ | |||||||||
| G | |||||||||
| G♯ / A♭ | |||||||||
| A | |||||||||
| A♯ / B♭ | |||||||||
| B |
How it works
- Each half step multiplies the frequency by about 1.0595 (the 12th root of 2), so 12 half steps double it: A3 is 220 Hz, A4 440 Hz, A5 880 Hz.
- From a frequency to a note: count the half steps from A4, which is 12 × log2(frequency ÷ 440), and round to the nearest whole number. 700 Hz is 8.04 half steps above A4: F5. This is the same as working out a frequency’s pitch.
- Cents measure what’s left over. A cent is a hundredth of a half step, so a note can be up to 50 cents sharp or flat before the next note is nearer. 700 Hz is 4 cents sharp of F5 (698.46 Hz): too little for most people to hear.
- From a note to a frequency: 440 × 2n/12, where n is the number of half steps from A4 (negative below it). This is equal temperament, the tuning of a piano and of every tuner.
Common frequencies
What note is…? At A4 = 440:
- 440 Hz is exactly A4: the tuning note, the A above middle C.
- 432 Hz is A4, 32 cents flat. At A4 = 432 tuning it is A4 itself.
- 256 Hz is C4, 38 cents flat. It’s sometimes called “scientific” middle C; in standard tuning middle C is 261.63 Hz.
- 528 Hz is C5, 16 cents sharp.
- 700 Hz is F5, 4 cents sharp.
- 1,000 Hz is B5, 21 cents sharp. A common test tone.
- 100 Hz is G2, 35 cents sharp.
- 60 Hz is B1, 49 cents flat, almost halfway to A♯1 (B♭1). The hum of US mains electricity.
- 50 Hz is G1, 35 cents sharp. The hum of mains electricity in the UK and Europe.
- 82.41 Hz is exactly E2, the guitar’s low E string.
Numbers like 396, 417, 528 and 963 Hz come from “solfeggio” and healing-music lists. Musically, each is simply near a note: type it in to see which.
A4 = 440, 432 or 442 Hz
- 440 Hz is standard concert pitch, used by tuners, pianos and most music. Start here.
- 442 Hz (sometimes 443) is used by many orchestras in Europe for a slightly brighter sound: every note is about 8 cents higher.
- 432 Hz tuning puts every note about 32 cents lower, about a third of a half step. Some musicians prefer its sound; the claims that it is more “natural” or healing have no scientific support. Switch the tuning above to hear the difference.
Using it in class
- The science of sound. Play A3, A4 and A5 and show that each octave doubles the frequency. The waves show why: twice as many in the same time.
- How high can you hear? Pick notes higher and higher in the table. (Laptop and phone speakers struggle below about 100 Hz, so the lowest notes may be quiet.)
- In tune or not? Type 440, then drag the needle slowly to the right: listen for when the difference becomes audible, and watch the two waves drift apart.
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Questions
What note is 432 Hz?
In standard tuning (A4 = 440), 432 Hz is A4, 32 cents flat: between G♯4 and A4, nearer A. In 432 tuning it is A4 exactly, by definition.
Is 432 Hz better than 440 Hz?
It’s lower, by about a third of a half step, and some people like its warmer sound. There is no scientific evidence that it is healthier or more natural. 440 Hz has been the international standard since 1955, so instruments, tuners and recordings use it.
What does “cents sharp” or “cents flat” mean?
How far the frequency is above (sharp) or below (flat) the nearest note, in hundredths of a half step. Most listeners notice a difference of about 5 to 10 cents between two notes played one after the other.
Why do some notes have two names?
C♯ and D♭ are the same key on a piano and the same frequency in equal temperament. Pick either with the ♯ and ♭ buttons: the frequency is the same.
Which octave is middle C?
The converter uses scientific pitch notation: middle C is C4 (261.63 Hz), and each octave starts on C. Some keyboards and music software call middle C “C3” instead.
Is this a tuner?
No. It turns numbers into notes and back. A tuner listens through the microphone; this never does. To hear a note to sing or tune to, the pitch pipe can hold it for as long as you need.