Key Signature Calculator

A key signature is the group of sharp or flat symbols printed after the clef at the beginning of a staff. It tells performers which pitches are normally raised or lowered throughout the music. This calculator identifies the signature for every conventional major key and natural minor key, lists its accidentals in their standard written order, and shows the relative key that uses exactly the same notes. That makes it useful for reading notation, checking a composition, preparing an arrangement, or reviewing music theory. Sharp signatures always accumulate in the order F sharp, C sharp, G sharp, D sharp, A sharp, E sharp, B sharp. Flat signatures use the reverse-style order B flat, E flat, A flat, D flat, G flat, C flat, F flat. A new key adds one accidental without changing the order of those already present. C major and A minor sit at the center with no sharps or flats. Moving clockwise around the circle of fifths adds sharps, while moving counterclockwise adds flats. Major and minor keys can share a signature while placing a different note at the tonal center. These pairs are called relative keys. C major is relative to A minor, G major is relative to E minor, and E flat major is relative to C minor. The shared signature does not mean the music sounds identical: melody, harmony, cadences, and emphasis establish which tonic feels like home. Harmonic and melodic minor passages may also introduce temporary accidentals that are not part of the printed key signature. Enter accidentals as a number sign or lowercase b, such as F# or Bb. The calculator also accepts the musical sharp and flat symbols. Enharmonic notes can sound at the same pitch but have different theoretical spellings, so F sharp major and G flat major produce different written signatures. The selected spelling matters to performers because it preserves scale-letter order and harmonic function. Use the result as a quick notation reference rather than a substitute for reading the musical context. Modal music, atonal scores, transposing instruments, and pieces that change key can require additional interpretation. For ordinary major and minor scales, however, the displayed signature follows standard circle-of-fifths conventions and provides an immediate, dependable answer.