Six free tools for the same job from different angles: figure out what a progression is doing, build a new one, move it, name a chord you found, or look up what fits a scale. Each runs in your browser, no account.
Paste a progression, get the key, the Roman numerals, the compatible scales and the mood. Handles sevenths, altered dominants and slash chords.
Use when: you have chords, you want to understand themClick or type a set of notes and it names the chord, the inversion, and any alternative spellings. 24 chord shapes across all keys.
Use when: you found a shape, you don't know its namePick a key and a mood — pop, sad, jazz, lo-fi, blues, cinematic — and get a progression with Roman numerals. Regenerate for a fresh one.
Use when: you have a blank pageMove a progression by semitones or from one key to another. Keeps sevenths, sus chords and slash bass. Includes a capo chart.
Use when: the key is wrong for a voice or an instrumentTurn a progression into Nashville numbers in any key, or numbers back into chords. One chart that plays in every key.
Use when: you want a key-independent chartChoose a root and a scale to see all seven diatonic chords, the scale notes, the Camelot position and common progressions — with audio.
Use when: you want the chords that fit a key or modeThe progressions most popular music is built on, in Roman numerals, with the songs that use each one and a button to hear it in any key.
Use when: you want a proven starting pointWell-known songs and the progression each one uses. Search a song, or filter by progression, genre or decade.
Use when: you want to know what a specific song doesThese tools describe one thing — harmony — from every practical direction. Here is the workflow they support.
Type the chords into the Analyzer. It tells you the key and labels each chord with its Roman numeral, so you stop seeing "C, Am, F, G" and start seeing "I, vi, IV, V" — a pattern you will recognise in a hundred other songs. If a chord in the chart has a name you do not know, check it in the Identifier.
Singers have a range; capos have limits. Put the progression through the Transposer, set the new key or the number of semitones, and it rewrites every chord — extensions and slash bass intact — with a capo suggestion for guitar.
Start with the Generator for a progression in the mood you want, then open the Scale & Chord Finder in the same key to see the other chords available — the ones the generator did not pick. Swap one in, listen, keep what works.
Run the final progression through the Nashville Number Converter. The number chart works in any key, so when the singer drops it a step at soundcheck, nobody rewrites anything.
The theory underneath all of it — how chords are built, why they resolve, what a key really is — is the Cloud Atelier music course, free and with no account. To see how keys relate on one diagram, open the Circle of Fifths.
A reference page for every common chord in every key — the notes and how they stack, the shape on a keyboard, a guitar shape and the full fretboard, plus the keys the chord belongs to.
For scales — notes, positions, and the chords in the key — see the Scale Library.