Circle of Fifths Calculator (Major) – Keys, Chords, Progressions & Transposing
Explore the circle of fifths, see key signatures & scale chords instantly – and transpose chord progressions with one click.
Example: Am F C G or F#m7 B7 Emaj7 (delimiters like spaces, commas, or lines are fine).
How to use the Circle of Fifths Calculator (Explanation)
The Circle of Fifths is the ultimate map for keys: it shows you which major and minor keys are closely related, how many sharps or flats a key has, and which chords "naturally" belong together. This is why it's so popular for songwriting, improvising, arranging, and teaching. This calculator makes the whole concept interactive: click a key in the circle (or select it from the dropdown) and immediately get the scale, accidentals, diatonic chords, and useful modulation shortcuts.
How to use this tool:
- Select a Key: Click C, G, D... in the circle or use the dropdown menu. The active key will light up, and all data will be displayed on the right.
- Notation Settings: Use "Prefer ♯ names" to decide if you want to see sharp or flat names (e.g., F# instead of Gb). For German-speaking musicians, there is the "H/B Notation" option: English B will be shown as H, and Bb as B, as standard in many Central European scores.
- Understand Accidentals: Under "Key Signature," you'll see the number of sharps (♯) or flats (♭) plus the exact order they appear. This helps with sight-reading and writing scales correctly.
- Scales & Relationships: You see the major scale (7 notes), the relative minor (same signature), and the parallel key. The Dominant (V) and Subdominant (IV) are also shown—perfect for simple modulations. Remember: "right" in the circle usually means more sharps, "left" means more flats.
- Chords Ready to Go: The calculator lists the diatonic chords (triads and optional sevenths) including Roman numerals (I–vii°). You also see the specific chord tones to help build voicings.
- Progression Ideas: Choose a style preset (Pop, Rock, Jazz, Blues) and get a typical chord progression both in Roman numerals and as actual chords in your key—ideal for songwriting and practice.
- Transposing: Paste a chord progression (e.g., "Am F C G") and choose a target key. The tool automatically shifts the root notes while keeping suffixes like "m7" or "add9" intact.
Why this brings real value:
- Faster Practice: Neighboring keys (a fifth apart) immediately feel "logical"—saving time during fretboard or piano training.
- Better Arranging: Dominant/Subdominant and relative keys are the most common areas for harmonization. Here they are visible with one click.
- Functional Understanding: When you see that V → I almost always sounds "resolved," you recognize cadence patterns in songs much faster.
- Avoid Errors: The order of accidentals is a classic hurdle in music theory—this calculator shows them cleanly and consistently.
FAQ
Why are there both # and b spellings?
Some keys are traditionally written with sharps (e.g., E Major), others with flats (e.g., Eb Major). Both describe the same tonal system, but readability is better depending on the context.
What does "relative minor" mean?
This is the minor key that shares the exact same key signature as the major key. Example: C Major and A Minor both have zero accidentals.
Which chords are "diatonic"?
These are chords built exclusively from the notes of the scale. In major keys, the qualities are: I, IV, V = Major; ii, iii, vi = Minor; vii° = Diminished.
What does "vii°" or "half-diminished" mean?
The seventh chord in a major scale contains a diminished fifth. In seventh chords, this often results in a m7♭5 sound (half-diminished), which leads strongly to the dominant or tonic.
Can I use this to modulate?
Yes: shift to the Dominant or Subdominant (neighbors in the circle) and use common chords as a bridge. This is the simplest, musically clean modulation.
Embed this Calculator on Your Website
You can integrate this calculator for free into your own website. Get the embed code on our overview page.