Music theory, calculated.
A deterministic, spelling-aware calculator for intervals and triads. No tutorials. No gamification. Just answers.
Download for iOSWhat is it?
Intervallo is a music theory calculator for iOS. It works exactly like the calculator app already on your phone, but for musical structure. Place notes on a grand staff, and Intervallo identifies the interval or chord immediately.
It is designed for musicians who already know music theory. It doesn't teach. It confirms, identifies, and names.
What is it good for?
Most music apps want to hold your hand. They lock you to a specific key, guide you through exercises, or guess at chord names using messy heuristics. That doesn't help when you're deeply analyzing a chromatic score.
Spelling matters. F to B is an Augmented 4th. F to C♭ is a Diminished 5th. They sound identical, but they mean very different things harmonically. Intervallo is spelling-aware. It treats them differently because you wrote them differently.
"If you wrote C♭, you meant C♭. Intervallo respects your notation."
Who is it for?
Intervallo is built for composers, post-grad students, and music theorists who need to identify the exact harmonic DNA of a cluster.
If a score shows two or three notes in the left hand without a complete chord, the calculator will tell you whether those notes constitute a recognized shell voicing and which seventh chord they imply. And crucially, if you place notes that do not form a recognized functional chord structure, it honestly returns "Not a triad." It preserves your ability to make contextual judgments rather than forcing a wrong name onto modern or chromatic writing.
The Math Behind the Music
We approach chord identification as a finite enumeration problem, not a pattern-matching guessing game. Within the constraint of three distinct pitch classes contained in one octave, the universe of possible interval structures is exactly fifty-five pairs.
The Triad Calculator covers every three-note structure in Western harmony—twenty-four named structures derived from a complete mathematical enumeration. It is a strictly verified, logic-driven approach to tonal harmony.