Song Key Calculator
Determine the musical key and mode from a chord progression. Get Roman numeral analysis, relative key, Camelot Wheel code for DJ harmonic mixing, and closely related keys.
Most Likely Key
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Relative Key —
Roman Numeral Analysis —
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Key
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Mode —
Roman Numerals —
Relative Key —
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Key Analysis
Key —
Roman Numerals —
Related Keys
Relative Key —
Parallel Minor/Major —
Closely Related Keys —
DJ / Harmonic Mixing
Camelot Wheel Code —
How to Use This Calculator
- Select a Chord Progression from the preset list.
- The calculator identifies the most likely key, mode, Roman numeral analysis, and relative key.
- Use the Camelot Wheel tab to find the DJ harmonic mixing code and compatible keys.
- The Professional tier shows closely related keys and all harmonic context.
Formula
Key identification matches the chord set against diatonic scale degree patterns. The Roman numerals I–VII (major) and i–vii° (minor) describe each chord's function within the key.
Example
Progression G D Em C: G = I, D = V, Em = vi, C = IV → G major (I–V–vi–IV). Relative key = E minor. Camelot = 9B. Compatible with D major (10B) and C major (8B).
Frequently Asked Questions
- Look for patterns in the chord progression. The most common progressions are I-V-vi-IV (C-G-Am-F in C major) and i-VI-III-VII (Am-F-C-G in A minor). The tonic chord (I or i) usually appears first and last and feels most "at rest."
- The Camelot Wheel is a system used by DJs to identify compatible keys for harmonic mixing. Keys are assigned numbers 1–12 with letters A (minor) or B (major). Adjacent numbers or the same number with opposite letter are harmonically compatible.
- A key describes the tonal center. A mode describes which scale pattern is used from that center. C major uses the Ionian mode (whole-whole-half-whole-whole-whole-half). A minor uses Aeolian. The same notes (C to C vs A to A) create different moods.
- Relative keys share the same key signature but have different tonic notes. C major and A minor are relative keys — both use no sharps or flats, but C major centers on C while A minor centers on A.
Related Calculators
Sources & References (5) ▾
- Chord Function and Key Identification — Berklee Online
- Hooktheory: The Science of Hit Songs — Hooktheory
- Harmonic Mixing with the Camelot Wheel — Mixed in Key
- Roman Numeral Analysis in Music Theory — Music Theory Academy
- The Cognition of Basic Musical Structures — MIT Press