Circle of Thirds
The Circle of Thirds organizes the 12 chromatic notes by major and minor third relationships — the building blocks of chord construction and chromatic mediant motion.
Outer ring = major thirds (4 semitones) · Inner = minor thirds (3 semitones)
Click any note on the circle to explore its third relationships.
While the Circle of Fifths shows key relationships, the Circle of Thirds groups notes that are a major third (4 semitones) or minor third (3 semitones) apart. These are the intervals that build triads — a root, a third, and a fifth. Chromatic mediants (chords related by thirds) create lush, unexpected harmonic color in film scores and jazz.
Circle of Thirds
The Circle of Thirds shows harmonic relationships between chords a major or minor third apart. Explore chromatic mediant relationships. Free music theory tool.
Circle of Thirds is a free browser-based tool from South Fork Apps. There's nothing to install, no account to create, and no usage limit. Open the page, do the work, and move on.
How it works
- Open Circle of Thirds in any modern browser on desktop or mobile.
- Enter or paste your input into the tool's main field.
- Adjust any options shown on the page to match what you need.
- Copy or download the result and continue with your work.
Why use a browser tool
Browser tools beat installable apps when the job is small. You don't have to manage updates, sign in, or wait for a heavy program to load. Circle of Thirds runs entirely in your browser. Your input never leaves your device, no analytics watch what you type, and the page stops working the moment you close the tab.
Privacy and data
South Fork Apps tools process everything client-side in JavaScript. No server sees your data. Nothing is stored, logged, or sent anywhere. If you're working with sensitive content, you can verify by opening the page once, disconnecting from the internet, and watching Circle of Thirds keep working.
