MIDI Note to Frequency
Convert a MIDI note number into its exact frequency in hertz.
About MIDI Note to Frequency
MIDI note 69 is the tuning note A4, and each semitone up doubles the frequency after twelve steps. Synth patches, sample pitch and tuning software all rely on this equal-tempered relationship between note number and hertz.
Formula
MIDI Note to Frequency
Frequency = 440 x 2^((MIDI-69)/12)
- MIDI
- MIDI note number, where 69 is A4
Worked example
With the default values below, MIDI Note to Frequency returns Frequency of 440.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- MIDI note numberaccepts 0–127
- 69
- A4 tuningaccepts 400–466 Hz
- 440 Hz
Results
- Frequency
- 440.00 Hz
- Wavelength
- 0.780 m
Step by step
- 1Values used
- 2MIDI Note to Frequency
- 3Frequency= 440.00 Hz
- 4Wavelength= 0.780 m
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is MIDI Note to Frequency calculated?
Frequency = 440 x 2^((MIDI-69)/12) MIDI note 69 is the tuning note A4, and each semitone up doubles the frequency after twelve steps.
Why does MIDI Note to Frequency matter?
Synth patches, sample pitch and tuning software all rely on this equal-tempered relationship between note number and hertz.
What values do I need to enter?
This calculator takes 2 inputs: MIDI note number, A4 tuning. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.