Detected Key
CMajor
Strong match
4/4 chords diatonic
Chord Analysis — click for diagram
Other Possible Keys
How to Use
- 1Click "Load example" to try a sample progression, or type your own chords into the input area.
- 2The key is detected instantly as you type. The top result shows the most likely key with a confidence percentage.
- 3The chord analysis shows the roman numeral role of each chord (I, IV, V, vi, etc.) in the detected key. Chords outside the key are shown in red.
- 4Click any chord in the analysis to see its finger position diagram. If two keys tie, they are relative keys — use the chord the song resolves to as the true tonic.
About the Guitar Key Finder
Guitar Tool Hub's free key finder analyzes your chord progression and instantly identifies the musical key. Paste any combination of chords — including complex shapes like Dm7, Gsus4, and Cadd9 — and the tool scores all 24 possible keys (12 major + 12 minor) based on how many chords are diatonic. The chord analysis displays the roman numeral role of each chord, and every chord is clickable to open a finger diagram.
- 01Detects major and minor keys from any chord progression
- 02Scores all 24 keys and ranks by confidence percentage
- 03Roman numeral analysis for every chord (I, IV, V, vi, ii°, etc.)
- 04Highlights chords that fall outside the detected key
- 05Explains relative key ties (e.g. C Major and A Minor)
- 06Clickable chord diagrams — free, no account needed
Frequently Asked Questions
The tool scores all 24 possible keys (12 major and 12 minor) by checking how many of your chords are diatonic — naturally belonging to that key's scale. The key with the most matching chords is shown first, along with a confidence percentage.
Relative major and minor keys share the same set of diatonic chords. C Major and A Minor contain the same seven chords, so a progression like C Am F G matches both perfectly. Listen for which chord the song 'resolves' or comes to rest on — that chord's root is usually the true tonic.
Roman numerals label each chord's position within a key. Uppercase (I, IV, V) means a major chord, lowercase (ii, vi) means minor, and a degree symbol (vii°) means diminished. The I chord is home base, the V chord creates tension that wants to resolve, and the IV chord adds movement. This system makes it easy to transpose a progression to any key.
Chords outside the detected key are highlighted in red and shown with a dash instead of a roman numeral. These are called borrowed or chromatic chords — common in many songs for emotional color. Their presence lowers the confidence score for that key but doesn't mean the detection is wrong.
Yes. The tool strips extensions (7ths, 9ths, sus, add) to identify the core quality of each chord, then matches it against the diatonic chords of each key. For example, G7, Gsus4, and Gadd9 all register as a G major chord for key detection purposes.
Yes. If you know the sounding chords (after the capo shifts the pitch), enter those directly. If you only know the chord shapes, enter the shapes and then use the Chord Transposer tool to shift by the capo fret number to find the sounding key.
Yes — completely free. No account, no download, and no payment required.