🍋 Audio Tools
Frequency Calculator
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About Frequency Calculator
Convert between note names, frequencies (Hz), MIDI numbers, and wavelengths. Supports custom concert pitch from A4=432 to 443 Hz.
How It Works
Enter a note name, frequency, or MIDI number to convert between all formats with wavelength and neighboring notes.
Frequently Asked Questions
Why is A4 tuned to 440 Hz?
Adopted as the ISO standard in 1955. Before standardization, concert pitch varied from 415 Hz (Baroque) to 450+ Hz.
Human hearing frequency range?
20 Hz to 20 kHz. Musical instruments: 27.5 Hz (A0) to 4,186 Hz (C8) plus overtones.