Circle of Fifths — Interactive Music Theory Tool | Key Signatures, Chords & Progressions | LazyTools
🎵 Music Tools

Circle of Fifths — Interactive Key Signatures, Chords & Progression Builder

Click any key to see its diatonic chords, key signature, relative minor, and scale notes. Build and play back chord progressions. Load common progressions like I–V–vi–IV and ii–V–I. Transpose to any key instantly. Web Audio chord synthesis. No download, no signup.

All 12 major keys Diatonic chords Progression builder Transposition Audio playback
ADSENSE — 728×90 LEADERBOARD
🎶 Circle of Fifths

Click any key — outer ring = major, inner ring = relative minor

Major key
Relative minor
Sharps/flats count
C major
Click any key to explore it
Key sig: No sharps or flats
Diatonic chords — click to play or add to progression
Scale notes
Progression builder
Click chords above to add them here
Common progressions
Transpose to key
ADSENSE — 728×90 LEADERBOARD
🎹
Hear those chords on a real piano?
The free Online Virtual Piano has a scale highlighter that shows exactly which keys belong to any key you are studying — perfect companion to the Circle of Fifths.
🎹 Virtual Piano →
⭐ User Ratings

Rate this tool

4.9
★★★★★
Based on 5,800 ratings
5
5,394
4
232
3
116
2
58
1
0
Did this help you understand music theory?
Thank you for your rating!
✔ Key Features

What makes this circle of fifths different from musicca and muted.io

🎵
Chord Progression Builder
Click diatonic chords to add them to a progression, then play back the sequence with Web Audio synthesis. Hear how I-V-vi-IV sounds in any key. No free competitor combines the circle with a built-in progression builder.
📚
Common Progressions Library
One-click presets for the most-used progressions: I-V-vi-IV, I-IV-V-I, ii-V-I (jazz), I-vi-IV-V (50s), I-IV-I-V, and more. Each loads the correct diatonic chords for the currently selected key.
🔄
One-Click Transposition
Build a progression in any key, then click any other key to transpose it instantly. The chord names update to reflect the new key while preserving the Roman numeral relationships. No re-building required.
📊
Full Diatonic Chord Display
All 7 diatonic chords per key with Roman numerals (I, ii, iii, IV, V, vi, vii°) and chord quality colour-coding. Major chords in indigo, minor in green, diminished in red. Click any to play or add to progression.
🔑
Key Signatures
Every key shows the exact number of sharps or flats and which notes they affect. Visually colour-coded: sharp keys in indigo, flat keys in violet, C in grey. All 7 scale notes listed individually.
🔁
Relative Minor Display
The inner ring of the circle shows the relative minor for every major key. Clicking either ring selects both and shows their shared key signature, reinforcing the relationship between parallel keys.
🔊
Web Audio Chord Synthesis
Every chord and progression plays back using the Web Audio API — no audio samples downloaded. Chords are synthesised from stacked oscillators tuned to the correct intervals. Instant, in-browser playback.
🎨
Colour-Coded Segments
Sharp keys are highlighted in indigo, flat keys in violet, the selected key pulsed in bright indigo. Closely related keys (subdominant IV and dominant V) are highlighted when a key is selected, making relationships immediately visual.
🎯
Enharmonic Keys Shown
Both spellings shown at the bottom of the circle: F#/Gb, C#/Db, B/Cb. Clicking either enharmonic spelling selects the same position. An explanation of why they exist is included in the key information panel.
📖 How to Use

How to use the circle of fifths

1
Click a key
Click any segment on the outer ring to select a major key. The inner ring shows its relative minor. The right panel instantly updates with key signature, diatonic chords, and scale notes.
2
Play chords
Click any of the 7 diatonic chords (I through vii°) to hear it played via the Web Audio API. Major chords are shown in indigo, minor in green, diminished in red.
3
Build a progression
Click chords to add them to the progression builder at the bottom of the right panel. Click Play to hear the sequence. Load a common progression preset as a starting point.
4
Transpose
With a progression built, click any key on the Transpose row to move the entire progression to that key. The Roman numeral relationships are preserved; only the note names change.
5
Learn the relationships
Adjacent keys on the circle share 6 of 7 notes. Moving clockwise by one step gives you the dominant (V). Moving counterclockwise gives the subdominant (IV). The inner ring always shows the relative minor.
📊 Comparison

LazyTools vs other circle of fifths tools

FeatureLazyToolsmusicca.commuted.iotonegym.corandscullard.com
Chord progression builder✅ Built-in❌ No❌ No❌ No❌ No
Common progressions library✅ 6 presets❌ No❌ No❌ No❌ No
One-click transposition✅ Yes❌ No❌ No❌ NoPartial
Full diatonic chords (7)✅ Yes✅ Yes✅ Yes✅ Yes✅ Yes
Scale notes listed✅ Yes❌ No✅ Yes❌ No✅ Yes
Audio chord playback✅ Web Audio✅ Yes❌ No❌ No❌ No
Key signature details✅ Notes listed✅ Yes✅ Yes✅ Yes✅ Yes
No signup required✅ Always✅ Yes✅ Yes✅ Yes✅ Yes
📋 Key Signature Reference

All 12 major key signatures

KeySharps/FlatsAccidentalsRelative minor
C majorNoneA minor
G major1 sharpF♯E minor
D major2 sharpsF♯ C♯B minor
A major3 sharpsF♯ C♯ G♯F♯ minor
E major4 sharpsF♯ C♯ G♯ D♯C♯ minor
B major5 sharpsF♯ C♯ G♯ D♯ A♯G♯ minor
F♯/G♭ major6 sharps / 6 flatsEnharmonicD♯m / E♭m
D♭ major5 flatsB♭ E♭ A♭ D♭ G♭B♭ minor
A♭ major4 flatsB♭ E♭ A♭ D♭F minor
E♭ major3 flatsB♭ E♭ A♭C minor
B♭ major2 flatsB♭ E♭G minor
F major1 flatB♭D minor
📐 Guide

Circle of Fifths Guide — Key Signatures, Chord Progressions, and Transposition

The circle of fifths is the single most useful diagram in Western music theory. Invented in its modern form in 1679 by Nikolai Diletsky, it organises all 12 major keys in a circle where each adjacent pair is exactly one perfect fifth apart (7 semitones clockwise, or equivalently a perfect fourth counterclockwise). The result is a compact visual that encodes key signatures, relative minors, diatonic chord relationships, and modulation paths all at once.

Why adjacent keys sound related

Two keys adjacent on the circle share 6 of their 7 scale notes. G major and C major differ by only one note (F vs F#). This near-identity is why moving between adjacent keys sounds smooth and natural — most of the harmonic material is shared. The further apart two keys sit on the circle, the fewer notes they share and the more dramatic a modulation between them sounds. Keys directly opposite each other (e.g. C and F#) share only 6 notes and represent the most distant harmonic relationship.

Circle of fifths and chord progressions

The circle predicts which chord movements have the strongest harmonic pull. The V chord (one step clockwise from the tonic) creates the strongest resolution back to I — the V–I movement is the backbone of Western cadences. The IV chord (one step counterclockwise) creates a different, softer pull. The ii–V–I progression in jazz is literally three consecutive steps counterclockwise around the circle, and its strength comes directly from this chain of descending fifths. Understanding this makes the I–V–vi–IV progression immediately obvious: you are visiting the dominant (clockwise), then the relative minor (shared key signature), then the subdominant (counterclockwise) before returning home.

Circle of fifths music theory free online — transposition

The most practical application of the circle for working musicians is transposition. If a singer needs a song in a higher or lower key, you locate the diatonic chords on the circle (they always sit at the same relative positions: I at the top, IV one step left, V one step right, vi two steps right). Moving the entire pattern clockwise raises the key by a fifth; counterclockwise lowers it by a fifth. Two steps clockwise raises by a whole tone. This geometric approach is faster than memorising transposition tables for all 12 keys.

❓ FAQ

Circle of fifths — 8 questions answered

A circular diagram arranging all 12 major keys where each adjacent key is a perfect fifth apart. Moving clockwise adds one sharp; counterclockwise adds one flat. It encodes key signatures, relative minors, and chord relationships.

The 7 chords built on each degree of a major scale using only notes within that key. Pattern: I (major), ii (minor), iii (minor), IV (major), V (major), vi (minor), vii° (diminished). For C: C, Dm, Em, F, G, Am, B°.

Every major key has a relative minor sharing the same key signature. The relative minor starts on the 6th scale degree. C major’s relative minor is A minor. G major’s is E minor. Shown on the inner ring of the circle.

Adjacent keys share 6 of 7 notes. V resolves strongly to I (clockwise to counterclockwise). The I-IV-V-I progression uses the three adjacent positions. The ii-V-I jazz progression moves 3 steps counterclockwise. Build any progression with the builder above and play it back.

Moving a chord progression from one key to another while preserving the harmonic relationships. Build a progression, then click any key in the Transpose row to see the chord names update for the new key.

Sharps: F-C-G-D-A-E-B (Father Charles Goes Down And Ends Battle). Flats: B-E-A-D-G-C-F (the reverse). Each clockwise step adds one sharp; each counterclockwise step adds one flat.

Key pairs that sound identical but are written differently. F# major (6 sharps) and Gb major (6 flats) are enharmonic. Both appear at the bottom of the circle. Musicians choose based on notational simplicity.

LazyTools Circle of Fifths is 100% free. No download, no account, no signup. Click any key for diatonic chords, key signatures, relative minor, and scale notes. Build progressions and transpose. Works in any modern browser.