Relative Minor Key Finder

Find properly spelled relative natural-minor tonic at major sixth and shared signature from conventional major key, retaining enharmonic spelling; no arbitrary pitch-class subtraction.

Description

A relative natural minor shares the major key’s signature while using its sixth degree as tonic.

A relative natural minor shares the major key’s signature while using its sixth degree as tonic. Correct spelling preserves that relationship.^[1]

Enter exact major tonic without octave whose signature has at most seven sharps/flats. Return spelled relative-minor tonic and signed shared count, positive for sharps and negative for flats.

When to use Relative Minor Key Finder

Use Relative Minor Key Finder when you need to evaluate the supplied records under the calculation and evidence rules below. No harmonic/melodic-minor alterations, parallel key or tuning are supplied.

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

How to use Relative Minor Key Finder 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 majorTonic using the field table and calculation rules, then run the tool.
Read relativeMinorTonic, sharedSignatureAccidentalCount. 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
majorTonic	Major tonic	string	Required

Enter exact major tonic without octave whose signature has at most seven sharps/flats. Return spelled relative-minor tonic and signed shared count, positive for sharps and negative for flats.

minorTonic=majorTonic+five letter steps/nine semitones

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

Output field	Meaning	Value type
relativeMinorTonic	Relative minor tonic	string
sharedSignatureAccidentalCount	Shared signature accidental count	number

json

{
  "input": {
    "majorTonic": "Ab"
  },
  "output": {
    "relativeMinorTonic": "F",
    "sharedSignatureAccidentalCount": -4
  }
}

Limitations and assumptions

No harmonic/melodic-minor alterations, parallel key or tuning are supplied.

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 Parallel Key Lookup: Parallel keys retain the same spelled tonic while changing major/natural-minor mode. Their signatures differ from relative-key signatures. For a complementary task, use Key Signature Accidental Count Lookup: A key signature is tied to spelled tonic and major/natural-minor mode. Enharmonic keys can carry different accidental counts.

References

Relative Minor Key Finder — tool.io

Similar or alternative tools

Parallel Key Lookup
Parallel keys retain the same spelled tonic while changing major/natural-minor mode. Their signatures differ from relative-key signatures.
Key Signature Accidental Count Lookup
A key signature is tied to spelled tonic and major/natural-minor mode. Enharmonic keys can carry different accidental counts.