MIDI Note Frequency Calculator
Convert a MIDI note number to equal-tempered frequency with adjustable concert pitch.
Your inputs
Calculation results
Formula & assumptions
Frequency = A4 × 2^((MIDI−69)/12).
Values use the specified units. Calculations use floating-point arithmetic. Check input measurements and formula assumptions before applying the result.
Compare your scenarios
Save up to five results to compare changes side by side. Scenarios stay in this tab until you clear or reload it.
Using MIDI Note Frequency Calculator
Convert a MIDI note number to equal-tempered frequency with adjustable concert pitch.
- Enter midi note, a4 reference using the units printed under each field.
- Choose Calculate, or enable live updates. Review the result labels and formula assumptions.
- Save scenarios to compare up to five variations, then copy the report or download JSON or CSV.
Example
MIDI note: 69 note number A4 reference: 440 hertz Frequency · hertz: 440 Octave number: 4 Pitch class · 0 is C: 9
Questions & answers
What does MIDI Note Frequency Calculator calculate?
Convert a MIDI note number to equal-tempered frequency with adjustable concert pitch.
Which units should I enter?
MIDI note uses note number. A4 reference uses hertz. Convert values to these units before calculating.
Which formula does it use?
Frequency = A4 × 2^((MIDI−69)/12).
What does the included example show?
MIDI note: 69 note number; A4 reference: 440 hertz. Result: Frequency · hertz = 440; Octave number = 4; Pitch class · 0 is C = 9.
Can I compare different settings?
Yes. Save a scenario, change the inputs and save another result. Up to five scenarios are compared in this tab; they disappear when you reload or leave.
Can I export the calculation?
Copy the JSON report or download JSON and CSV with inputs, result labels and numeric values. Processing uses local JavaScript; no calculation request is sent to our server. Displayed values use up to 10 significant digits; exports retain JavaScript numeric precision.
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