Calculadora de Frequência de Nota
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
f = 440 × 2^((n − 69)/12)
About this calculator
This calculator converts a MIDI note number (0 to 127) into its corresponding sound frequency in Hertz. It uses equal temperament, where A4 (MIDI 69) is set to 440 Hz. The formula is f = 440 × 2^((n − 69)/12), which distributes the 12 notes of the octave logarithmically.
To use, simply enter the MIDI note number. The result gives the exact frequency, useful for musicians, producers, and sound engineers who need to tune synthesizers, adjust instrument pitch, or understand the relationship between notes and frequencies. The calculator covers the full MIDI range from C0 (MIDI 0) to G9 (MIDI 127).
Use cases include programming synth patches, checking instrument tuning against a MIDI note, or exploring the mathematical relationship between notes and frequencies. Remember that human pitch perception is logarithmic, so each octave doubles the frequency.
Frequently asked questions
What does MIDI 69 mean?
MIDI 69 is the number representing the note A4 (A above middle C), with a standard frequency of 440 Hz. It is the tuning reference.
Can I use this calculator to tune an instrument?
Yes, you can. Play the note on your instrument, measure the frequency with a tuner, and compare it to the calculated value for the corresponding MIDI note.
Does the formula work for notes outside the MIDI range?
The formula is based on the MIDI standard range of 0 to 127. Notes outside this range can be calculated but do not correspond to standard MIDI notes.
What is the difference between frequency and note?
A note is a name given to a specific frequency within a musical system. Frequency is the physical measurement in Hertz. Each note corresponds to a specific frequency.