Calculadora de Transposição
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
dest = (nota + trans) mod 12
About this calculator
The Transposition Calculator is a practical tool for musicians who need to transpose musical notes quickly and accurately. It takes a note represented by a number from 0 to 11 (where 0 corresponds to C, 1 to C sharp/D flat, and so on) and a transposition value in semitones, which can be positive (up) or negative (down). The result is the transposed note, also in the 0 to 11 range.
The operation is simple: the original note is added to the transposition value and the result is adjusted to the 0 to 11 range using the modulo 12 operation. For example, if you have note 7 (G) and want to transpose 5 semitones up, the calculation is (7 + 5) mod 12 = 12 mod 12 = 0, resulting in C. This ensures the note always stays within the octave, regardless of the transposition value.
This calculator is useful in various musical situations: when transposing a melody to a key more suitable for a singer's voice, when adjusting chords in an arrangement, or when studying music theory. It is especially valuable for beginners learning the relationship between notes and intervals, as it allows quick visualization of a transposition result without manually counting semitones.
Important considerations: remember that the calculator works only with notes within one octave (0 to 11). If you need to transpose a melody spanning multiple octaves, you must apply the transposition to each note individually. Also, the tool does not consider enharmonic equivalents (differences between C sharp and D flat), treating all notes as numbers. For practical use, you can associate the numbers with your preferred note names.
Frequently asked questions
How do I know which number corresponds to which note?
The standard mapping is: 0 = C, 1 = C sharp/D flat, 2 = D, 3 = D sharp/E flat, 4 = E, 5 = F, 6 = F sharp/G flat, 7 = G, 8 = G sharp/A flat, 9 = A, 10 = A sharp/B flat, 11 = B. You can use this reference to convert notes to numbers.
Can I transpose by more than 12 semitones?
Yes, you can use any integer value, positive or negative. The calculation uses modulo 12, so transposing by 12 semitones results in the same note (one octave up). For example, transposing 0 by 12 gives 0.
Does the calculator consider accidentals (sharps and flats)?
The calculator only handles numbers, it does not distinguish between sharps and flats. Each number represents a note, regardless of naming. You can interpret the result as you prefer.
What is the difference between transposition and modulation?
Transposition is shifting all notes of a melody by a fixed interval. Modulation is changing the key within a piece, often involving harmonic changes. This calculator performs only transposition.
Do I need to consider different octaves?
The calculator works only with notes within one octave (0 to 11). If your melody uses notes in multiple octaves, you must transpose each note individually, keeping the original octave or adjusting as needed.