Music theory flashcards: intervals and key signatures for iPhone

Two small drills every musician eventually needs cold: the thirteen interval names from unison to octave, asked by semitone count, and all thirty major and minor key signatures.

Download the deck

43 cards · 19 KB · free · updated August 7, 2026

43 cardsFree

What’s inside

The interval cards run from 0 to 12 semitones, one card each: see "7 semitones," answer "perfect fifth." The six-semitone card is the tritone and carries both spellings, augmented fourth and diminished fifth, since which one you write depends on context the card can't supply.

The key signature cards ask by count: "3 sharps — major key" wants A major, "3 sharps — minor key" wants F♯ minor. All fifteen majors and fifteen minors are here, including the enharmonic edge cases (F♯ and G♭, C♯ and D♭, B and C♭ each get their own card). The speak button is off; no synthesizer says "A4 / d5" or "B♭" gracefully.

Sample cards

Front	Back
7 semitones	Perfect fifth (P5)
3 sharps — major key	A major
5 flats — minor key	B♭ minor

Who it’s for

Theory students, AP Music Theory candidates, and adult learners returning to an instrument. The deck assumes you already know what a key signature is; it makes the recall instant, it doesn't teach the concept.

Getting it onto your iPhone

Tap the download button on this page in Safari, open the download (the ↓ button by the address bar), and tap the file; it imports into Flickdeck as a new deck with every card unstudied. From a Mac or PC, download it and AirDrop it to your iPhone. The deck library page has the full walkthrough, and Flickdeck is available on the App Store.

Source and accuracy

Standard Western tonal theory, checked against the circle of fifths: sharps add in F-C-G-D-A-E-B order, flats in the reverse. Interval names follow the common practice naming for 0–12 semitones, with the tritone's two spellings on one card.