Calculate equal-tempered note frequency

A4 defaults to 440 Hz but can be adjusted for alternate concert pitch. This is a mathematical pitch reference, not a measurement of an instrument or recording.

Note

Octave

A4 reference

—Frequency

—MIDI note

—Wavelength at ~343 m/s

—Period

ReadyFrequency follows 12-tone equal temperament relative to the chosen A4 reference.

Use reference tones at a comfortable device volume and for brief checks. This tool does not measure safe listening level or hearing risk.

Browser-local music practice workflow

v10.79 connects timing, tuning, pitch reference, virtual instruments and music-theory tools without requiring an account. Existing interactive engines remain intact while the new workflow makes it easier to move from a practical task—keep time, tune, play, identify, transpose—to the next relevant tool.

Audio and theory boundaries

Microphone pitch detection depends on the device, room and signal quality. Equal-tempered frequency math does not measure a real instrument, and chord/scale naming can have multiple enharmonic or theoretical interpretations. Reference tones and noise should be used at comfortable playback levels; browser controls do not measure sound-pressure exposure.

How to use this Note Frequency Calculator

Calculate an equal-tempered note frequency from note name, octave, and reference A4 pitch, with MIDI and wavelength context.

Enter, paste, upload, or choose the inputs shown in the tool above.
Adjust the available options for the result you need.
Review the output before copying, downloading, or using it elsewhere.

What this tool does

Choose a note and octave, adjust concert pitch, and calculate or play the equal-tempered frequency directly in your browser.

Practical tips and limits

Review the inputs and result before using the output elsewhere. Keep the original data when the operation changes or replaces content.