Online Instrument Tuner
Generate reference tones with rich harmonics for tuning guitar, bass, ukulele, and violin. Fine-tune by cents with adjustable A4 reference pitch.
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Frequently Asked Questions
How does the Online Instrument Tuner work?
The tuner calculates the exact target frequency from the MIDI note number using the formula freq = A4 * 2^((note-69)/12), where A4 defaults to 440 Hz but is user-adjustable. It then creates a Web Audio API OscillatorNode at that frequency layered with harmonics to produce a rich reference tone that is easier to pitch-match by ear than a pure sine wave.
What instruments can I tune?
Guitar (standard and alternate tunings), bass, ukulele, violin, and any instrument that can tune by ear to a reference pitch. Select your instrument and string to hear the target note.
Can I adjust the A4 reference pitch?
Yes. The default is A4 = 440 Hz (concert pitch), but you can adjust it. Some orchestras tune to 442 Hz, and historical performances may use 415 Hz or other references.
How do I tune by ear with this tool?
Play the reference tone for each string, then tune your instrument until the pitches match. When the frequencies are close, you will hear a wobbling effect (beating) that slows down and disappears as you reach the correct pitch.