How to use this calculator
Convert note names and octaves into frequencies using equal temperament tuning.
How the calculation works
- Choose a note and octave.
- Adjust the A4 reference tuning if needed.
- The result is calculated from the MIDI note distance from A4.
Formula
Frequency = tuning x 2 ^ ((MIDI note - 69) / 12).
Example
A4 at 440 tuning is 440 Hz, and A5 is 880 Hz.
Understanding your result
Use the output as a practical starting point, then review it before using it in an important workflow.
Assumptions and limitations
- This uses 12-tone equal temperament.
- Real instruments and alternate temperaments can differ.
Frequently asked questions
Does this require an account?
No. The core tool works without creating a Tool2Do account.
Is my input included in share links or analytics?
No. Tool2Do share actions use the tool page URL and safe metadata, not private values or uploaded files.