440 Hz Tuner: Tune Any Instrument to Concert Pitch
Tuner settings
🎶 Tune by ear 🎶
Our 440 Hz tuner is a free online tuner set to standard concert pitch, A = 440 Hz. That is the reference nearly all music assumes: the A above middle C at 440 hertz, with every other note calculated from it, and it is what guitars, keyboards, backing tracks and recorded music have been built around since the middle of the twentieth century. The 440 Hz tuner above is already on it — click Start Tuner, allow your microphone and play a note, and it will name the nearest note and tell you how many cents sharp or flat you are. It is fully chromatic, so it will tune any instrument you can play into a microphone. And because this page sets the reference from its own address, it overrides whatever you saved last: if you have been playing at 432 or at 442, this is the one-click way back to concert pitch. Nothing to install, nothing to pay, and the audio never leaves your device.
Note frequencies at A = 440 Hz
These are the frequencies every other reference pitch is measured against. The octave above middle C at standard concert pitch:
- C4: 261.63 Hz
- C#4: 277.18 Hz
- D4: 293.66 Hz
- D#4: 311.13 Hz
- E4: 329.63 Hz
- F4: 349.23 Hz
- F#4: 369.99 Hz
- G4: 392.00 Hz
- G#4: 415.30 Hz
- A4: 440.00 Hz
- A#4: 466.16 Hz
- B4: 493.88 Hz
Every other octave is a doubling or a halving of these: A3 is 220 Hz, A5 is 880 Hz, and so on down and up.
Open string frequencies at 440 Hz
Standard tuning for the common stringed instruments, lowest string first:
- Guitar (E A D G B E): 82.41, 110.00, 146.83, 196.00, 246.94, 329.63 Hz
- Bass (E A D G): 41.20, 55.00, 73.42, 98.00 Hz
- Ukulele (G C E A): 392.00, 261.63, 329.63, 440.00 Hz
- Violin (G D A E): 196.00, 293.66, 440.00, 659.26 Hz
- Viola (C G D A): 130.81, 196.00, 293.66, 440.00 Hz
- Cello (C G D A): 65.41, 98.00, 146.83, 220.00 Hz
These are the numbers printed on the back of every string packet and assumed by every piece of sheet music that does not say otherwise.
Tune your instrument to 440 Hz
- Find somewhere reasonably quiet and put your instrument near the device’s microphone.
- Click Start Tuner and allow microphone access when asked. Nothing is recorded or sent anywhere — the pitch analysis runs in your browser.
- Check the reference reads 440. This page sets it, so it will be there even if you saved something else.
- Play one note at a time, letting it ring rather than damping it. The tuner names the nearest note and shows how many cents sharp or flat you are.
- Adjust until the reading settles in the middle, then move on.
- Go round a second time. Tightening one string changes the tension on the others, so a single pass is never enough.
If your instrument keeps drifting flat after tuning, it is usually new strings stretching rather than anything wrong. Tune it, play it hard for a minute, tune it again, and repeat until it holds.
History of 440 Hz as concert pitch
Standard pitch is a recent idea. For centuries the local organ decided what pitch a town played at, and surviving instruments show variation of nearly a whole tone between one city and the next — which is why baroque specialists work at 415 Hz today, roughly a semitone below modern pitch.
The push to standardise ran through the nineteenth century. A congress of physicists in Stuttgart proposed 440 Hz in 1834. France went the other way in 1859, fixing diapason normal by law at A = 435 Hz to stop singers being pushed ever higher. An international conference in London adopted 440 Hz in 1939, and the International Organization for Standardization published it as ISO 16 in 1955, reaffirming it in 1975. That is the standard still in force.
In practice orchestras never fully complied. Many European ensembles work at 442 or 443 Hz, and the drift upward has not really stopped. 440 Hz is the reference everything else is measured against rather than the reference everyone uses.
Who tunes to 440 Hz
- Almost everyone, by default. Guitars, keyboards, tuning apps and pedal tuners all ship at 440 Hz.
- Anyone playing along to a recording. The overwhelming majority of recorded music since the 1950s is at or very near 440 Hz.
- Bands with a keyboard or any fixed-pitch instrument. A piano is tuned once or twice a year and cannot be moved to meet you, and most are at 440.
- Anyone who has drifted and wants to get back. If you have been experimenting with other references, this page resets you to the standard in one click.
Understand our 440 Hz tuner’s settings
The tuner above is our full chromatic tuner with the reference pitch already set for you. The first settings sit beside the tuner; the rest are behind Advanced settings.
The reference pitch of our 440 Hz tuner
This is the setting the page exists for, and it is already at 440 Hz. The address sets it, which means it takes precedence over anything you have saved before — this page opens at 440 Hz even if your usual reference is something else. You are not locked to it: type another value in the box or drag the slider and every note recomputes as you move. Any three digits followed by -hz in the address work the same way, so /432-hz-tuner, /442-hz-tuner and /444-hz-tuner open at those references, and /guitar-tuner/432-hz combines a reference pitch with an instrument.
Choose which microphone our 440 Hz tuner listens to
If your device has more than one input — a built-in microphone, a headset, an audio interface with your instrument plugged straight into it — pick the right one from the microphone list before you start. A direct signal from an interface is far steadier than a laptop microphone picking your instrument up across the room.
Set the sensitivity of our 440 Hz tuner
The confidence threshold decides how sure the detection algorithm has to be before it commits to a note. Raise it and the tuner ignores everything it is not certain about: fewer readings, but the ones you get are trustworthy. Lower it and it will follow a quieter or messier signal, at the cost of the occasional wrong note. Working at 440 Hz you are chasing a few cents, so a reading that holds still is worth more than one that reacts quickly.
Using our 440 Hz tuner in a noisy room
The noise gate sets a volume below which the tuner does not listen at all. Air conditioning, traffic, someone else practising in the next room — anything under the threshold is discarded before the pitch analysis runs. Raise it until the readout falls quiet when you stop playing, and leave it there.
Meter tuner or slider tuner
A matter of taste rather than accuracy. The Display the slider tuner switch swaps the needle for a horizontal slider; both read the same pitch to the same precision. Players tuning by feel tend to prefer the needle, players watching for drift over a long note tend to prefer the slider.
Save the settings of our 440 Hz tuner
Save settings stores your reference pitch, microphone, sensitivity, noise gate and display choice for next time. Reset settings puts all of them back to default. Note that the saved reference pitch applies across the site, so if you save here, our other tuners will open at 440 Hz too — which is usually what you want if 440 Hz is where you actually work.
To hear concert pitch rather than read it, our online tuning fork rings A = 440 Hz and our online tone generator will hold any frequency you name. Our online pitch detector shows the raw frequency of a note with no reference pitch applied. For tuning a particular instrument, use our guitar tuner, our bass tuner, our violin tuner or our chromatic tuner.
