Tune any instrument to standard concert pitch, A4 = 440 Hz. Almost every modern instrument and recording uses this reference.
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A4 = 440 Hz
Any instrument
Private, on-device
Reference pitch (A4)
Hz
Lower it in noisy rooms
Concert pitchA4 440 Hz
Press Start tuning, then play or sing a note
Detected note
Concert pitch
Reference octave
Frequency
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Target
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Deviation
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Clarity
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Note frequencies (octave 4)
A4 = 440 Hz
Note
Frequency
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
The international standard
A4 = 440 Hz is the reference pitch set by the international standard ISO 16. Every other note is calculated from it. For example, middle C is 261.63 Hz and the low E of a guitar is 82.41 Hz.
This page sets the tuner to 440 Hz for this visit. To hear the reference note instead of measuring, strike the tuning fork.
A4 = 440 Hz is the international standard pitch, so tuning to it keeps you in tune with almost every other instrument and recording.
How to use it
Press Start tuning and play a steady note. The page sets A4 to 440 Hz for this visit, and every note is calculated from it.
Frequently asked questions
Why is A4 = 440 Hz the standard?
In the past, pitch standards were very different from place to place. In the 20th century, 440 Hz was agreed internationally and published as ISO 16, so instruments and recordings everywhere match.
Do orchestras use 440 Hz?
Many do. Others prefer slightly higher pitches, such as 442 Hz, for a brighter sound.
How do I go back to my own setting?
This page only uses 440 Hz while it is open. The other tuner pages still use your saved reference pitch.
