Note Frequency Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
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Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the number of semitones from A4 (440 Hz).
- Read the frequency.
How it works
Frequency = 440 × 2^(semitones ÷ 12) — equal temperament.
Worked example
+3 semitones from A4. = 523.25 Hz (C5).
Common mistakes
- Forgetting +12 semitones = one octave (double the frequency).
- Using a different reference pitch (some use A4 = 442 Hz).
Frequently asked questions
Why is A4 440 Hz?
It's the modern concert-pitch standard; the whole equal-tempered scale is built around it.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.