Pitch & Key
Transposition Calculator
Pick a starting note and how many semitones to move. See where it lands, in both directions, plus what the interval is called. Useful for pitching samples, matching vocal keys, or planning a modulation.
Counting semitones
result = (start index + semitones) mod 12
The twelve notes form a cycle. Number them 0–11 (C = 0), add your semitone shift, and wrap around with mod 12. C + 5 semitones = index 5 = F, a perfect fourth up. Moving down works the same way with negative numbers. Because it's a cycle, +12 or −12 brings you back to the same note an octave away.
Pitching samples and planning key changes
When you pitch a sample up or down in your DAW, you're transposing by semitones, and this tells you the note you'll land on so you can match it to your track's key. Vocal samples are the common case: a topline recorded in one key can be shifted to fit yours, though pushing past about ±3 semitones starts to sound obviously processed unless you use formant-corrected pitching.
The named intervals matter for how a shift feels: a perfect fifth (+7) sounds strong and consonant, a tritone (+6) tense, a perfect fourth (+5) stable. If you're modulating a track up for energy, +2 (a whole step) is the classic "key change" lift; +1 is subtler and sneaks up on the listener.