EXAMPLE 1
Middle C
C4 · A4 = 440 Hz
261.63 Hz
Nine semitones below A4, middle C is a common reference for tuning oscillators and resonant filters.
Pitch calculator
Note Frequency Calculator
Find the frequency of any equal-tempered note, compare octaves and recalculate the entire tuning table from a custom A4 reference.
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Core formula
frequency = A4 × 2^((MIDI note - 69) / 12)
one semitone ratio = 2^(1 / 12)
one octave up = frequency × 2
one octave down = frequency / 2
MIDI note 69 is A4. Middle C is MIDI note 60, which gives 261.63 Hz when A4 is 440 Hz.
From note names to frequency
In 12-tone equal temperament, every semitone multiplies frequency by the twelfth root of two. Moving up twelve semitones doubles the frequency; moving down twelve halves it.
The usual reference is A4 = 440 Hz, but orchestras, historical practice and sound-design workflows may use another value. Amanita recalculates every note immediately when the reference changes.
Worked examples
Concrete values you can verify in the calculator and transfer directly to a production session.
EXAMPLE 2
F-sharp below middle C
F#3 · A4 = 440 Hz
185.00 Hz
Useful when matching a sub, resonator or filter peak to the key of F-sharp.
EXAMPLE 3
Alternative concert pitch
C4 · A4 = 432 Hz
256.87 Hz
Changing the reference shifts the entire table while preserving equal-tempered intervals.
| Note | Semitones from A4 | A4 = 440 Hz | A4 = 432 Hz |
|---|---|---|---|
| F#3 | -15 | 185.00 Hz | 181.63 Hz |
| A3 | -12 | 220.00 Hz | 216.00 Hz |
| C4 | -9 | 261.63 Hz | 256.87 Hz |
| C5 | +3 | 523.25 Hz | 513.74 Hz |
| D#5 | +6 | 622.25 Hz | 610.94 Hz |
Use it in a session
The calculator is deliberately direct: set the musical context, inspect the result and copy it where you need it.
- Set the A4 referenceUse 440 Hz or enter a value from 400 to 480 Hz.
- Find the note and octaveScan the chromatic table from octave 0 through octave 8.
- Copy the frequencyClick a cell and paste the value into an oscillator, EQ, resonator or analyzer.
Where it helps
Synthesis
Tune oscillators, comb filters and resonators to exact pitches.
Mixing
Locate the fundamental or harmonic region of a note in an EQ or spectrum analyzer.
Instrument setup
Compare measured pitch with the expected equal-tempered frequency.
Alternative tuning
Rebuild the frequency table around a concert pitch other than A4 = 440 Hz.
Studio note: A note name alone is not enough: always include the octave. C3, C4 and C5 share a pitch class, but each octave doubles the frequency.
Calculate it in Amanita
Open the exact tool with your saved tempo and tuning values intact. Nothing to install, no account and no ads.