Transpose Note By Interval

Transpose by separate signed diatonic/chromatic displacement to preserve intended interval spelling, unlike simple MIDI addition/capo offset; output must be MIDI-range and at most double accidental.

Description

Spelled transposition specifies both written-letter movement and semitone movement.

Spelled transposition specifies both written-letter movement and semitone movement. A semitone shift alone cannot preserve interval spelling.^[1]

Enter exact scientific pitch and signed integer diatonic steps −28…28/chromatic semitones −48…48. Return normalized target spelling and MIDI note; result must fit 0–127 and at most double accidentals.

When to use Transpose Note By Interval

Use Transpose Note By Interval when you need to evaluate the supplied records under the calculation and evidence rules below. Diatonic steps count letter transitions, not interval ordinal. No key signature, tuning or audio conversion is performed.

Enter the written notes, explicit grouping, pitch observations or supported chord tokens requested. Keep scientific octaves, accidentals and caller evidence consistent.

How to use Transpose Note By Interval and understand its results

Enter the written notes, explicit grouping, pitch observations or supported chord tokens requested. Keep scientific octaves, accidentals and caller evidence consistent.
Enter scientificNote, signedDiatonicSteps, signedChromaticSemitones using the field table and calculation rules, then run the tool.
Read transposedScientificNote, transposedMidiNote. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
scientificNote	Scientific note	string	Required
signedDiatonicSteps	Signed diatonic steps	number	Required
signedChromaticSemitones	Signed chromatic semitones	number	Required

targetMIDI=sourceMIDI+semitones; targetLetterIndex=sourceIndex+letterSteps

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
transposedScientificNote	Transposed scientific note	string
transposedMidiNote	Transposed midi note	number

json

{
  "input": {
    "scientificNote": "C4",
    "signedDiatonicSteps": 1,
    "signedChromaticSemitones": 3
  },
  "output": {
    "transposedScientificNote": "D#4",
    "transposedMidiNote": 63
  }
}

Limitations and assumptions

Diatonic steps count letter transitions, not interval ordinal. No key signature, tuning or audio conversion is performed.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Note Name to MIDI Converter: Scientific pitch notation combines letter, accidental and octave. Accidentals can cross the written octave boundary while sounding as one MIDI note. For a complementary task, use Diminished/Augmented Interval Classifier: Interval number follows letter distance while interval quality follows semitone distance. A tritone may be an augmented fourth or diminished fifth.

References

Transpose Note By Interval — tool.io

Similar or alternative tools

Note Name to MIDI Converter
Scientific pitch notation combines letter, accidental and octave. Accidentals can cross the written octave boundary while sounding as one MIDI note.
Diminished/Augmented Interval Classifier
Interval number follows letter distance while interval quality follows semitone distance. A tritone may be an augmented fourth or diminished fifth.