Music theory students
Check interval homework with the interval calculator. Music theory rules that look abstract on paper, such as spelling and the 9 and 12 rules for inversions, click once you can test them.
Interval Calculator: Name Any Interval and Count Semitones
ToMIDI is a free music interval calculator. Pick two notes and it names the interval and its quality, counts the semitones, gives the size in cents and the frequency ratio, shows the inversion and the compound form, then plays it to you one note after the other or both at once. Work the other way to find the note an interval lands on, or measure the distance between two keys in semitones. Every answer is drawn on a piano, right in your browser, with no sign-up.
- Semitones and Cents
- Hear Every Interval
- Free, No Sign-up
- Key to Key Distance
Free · runs in your browser
From
C4
261.63 Hz
Oct 4
Respell as
To
G4
392 Hz
Oct 4
Respell as
Clicking a key sets the To note next. · Space Melodic · H Harmonic · S Swap · ←→ semitone · ↑↓ octave
Interval
Perfect fifth
P5AscendingPerfect consonance
C4 G4
Semitones
7
3.5 whole steps
Cents
700¢
equal temperament
Frequency ratio
1.4983
2^(7/12)
Just ratio
3:2
701.96¢ · -1.96¢ equal-tempered offset
Inversion
Perfect fourth
P4 · 5 semitones
Compound form
Perfect twelfth
P12 · 19 semitones
C4
261.63 Hz
G4
392 Hz
ratio 1.4983
Same size, spelled differently: Diminished sixth (d6).
Interval chart from C
| Semitones | Interval | Example | Just ratio | Consonance |
|---|---|---|---|---|
| 0 | Perfect unison (P1) | C → C | 1:1 | Perfect consonance |
| 1 | Minor second (m2) | C → D♭ | 16:15 | Dissonance |
| 2 | Major second (M2) | C → D | 9:8 | Dissonance |
| 3 | Minor third (m3) | C → E♭ | 6:5 | Imperfect consonance |
| 4 | Major third (M3) | C → E | 5:4 | Imperfect consonance |
| 5 | Perfect fourth (P4) | C → F | 4:3 | Perfect consonance |
| 6 | Augmented fourth (A4) | C → F♯ | 45:32 | Dissonance |
| 7 | Perfect fifth (P5) | C → G | 3:2 | Perfect consonance |
| 8 | Minor sixth (m6) | C → A♭ | 8:5 | Imperfect consonance |
| 9 | Major sixth (M6) | C → A | 5:3 | Imperfect consonance |
| 10 | Minor seventh (m7) | C → B♭ | 16:9 | Dissonance |
| 11 | Major seventh (M7) | C → B | 15:8 | Dissonance |
| 12 | Perfect octave (P8) | C → C | 2:1 | Perfect consonance |
What an Interval Calculator Tells You
An interval is the distance between two notes, and an interval calculator gives it a name with two parts. The number counts letter names from the first note to the second, both included: C to E covers C, D and E, so it is a third. The quality comes from the semitones: a third of 4 semitones is major, a third of 3 is minor. That is why C to F sharp is an augmented fourth while C to G flat is a diminished fifth, even though both are 6 semitones on the piano. The interval calculator spells it the way you wrote it, then adds what a teacher would: the size in cents, the frequency ratio of the pure interval, its inversion and its compound form an octave higher. To see intervals stacked into whole chords, try the chord finder.
Calculate an IntervalWhy Intervals Are Easy to Get Wrong by Hand
Counting on your fingers works until one of these turns up. Each is a classic mistake the interval calculator gets right every time:
- Counting the gaps instead of the notes: C to E is a third, not a second, because both C and E are counted.
- Spelling: C to D sharp is an augmented second and C to E flat a minor third, although they sound the same.
- Direction: from C up to A is a major sixth, from C down to A a minor third.
- Crossing the octave: C to the D above the next C is a major ninth, 14 semitones, not a second.
- White keys that are not a whole step apart: E to F and B to C are only one semitone each.
Why Use This Interval Calculator
A basic semitone calculator stops at a number. This one names, measures, flips and plays the interval as well.
The full name, spelled right
Quality and number, such as minor sixth or augmented fourth, with the short form (m6, A4) and the spelling of both notes.
Semitones, cents and ratio
The semitone count in half and whole steps, the size in cents (100 per equal-tempered semitone) and the pure frequency ratio, side by side.
Inversion and compound form
See what the interval becomes when you flip it and what it is called an octave wider, so a major third, a minor sixth and a major tenth line up.
Note plus interval
Pick a starting note and an interval, and the note interval calculator lands on the target, up or down, spelled right.
Key to key distance
Pick two keys to see how many semitones apart they are, both up and down, before you transpose a song or a part.
Hear it both ways
Play the interval melodically, one note after the other, or harmonically, both at once, with the keys lit on the piano.
How to Use the Interval Calculator
Four steps, a few seconds, and the interval calculator shows its working on the keys.
Choose a letter, an accidental and an octave, or click a key on the piano. Sharps and flats stay as you spell them, and Respell swaps to the other name.
Choose a second note to measure the gap, or choose an interval and a direction to find where it lands.
The interval calculator shows the name, quality, semitones, cents, ratio, inversion and compound form at once, with both keys marked on the piano.
Hear the interval melodic or harmonic, and swap the two notes to hear it descending.
Step 1 · Pick the first note
Music Interval Calculator Features
Everything a music theory interval calculator should answer, from homework to studio work.
A semitone calculator with cents and ratios
As a semitone calculator it counts the half steps between any two notes, across octaves too. Next to the count you get the size in cents, 100 for each equal-tempered semitone, and the frequency ratio of the pure interval: 3:2 for a perfect fifth, 5:4 for a major third. Those ratios explain why a piano fifth (700 cents) sounds a touch different from a choir tuning by ear (about 702). Each result is also marked as a perfect consonance, an imperfect consonance or a dissonance.
Measure an IntervalInversions and compound intervals
Flip an interval and the numbers add up to 9 while the semitones add up to 12: a major third (4) inverts to a minor sixth (8), a perfect fourth to a perfect fifth. Widen it by an octave and it becomes compound, a major third turning into a major tenth of 16 semitones. So it works as a compound interval calculator too, handy for wide piano voicings and bass lines.
Flip an IntervalFrom a note and an interval to the target note
Start on E flat, go up a major sixth, and the note interval calculator lands on C, spelled as C rather than B sharp because a sixth must use the sixth letter name. Go down a perfect fourth from D and you get A. In the interval calculator, intervals run up to two octaves, with buttons to step one size smaller or larger. It is the quick way to build a harmony line, check a transposing instrument or find the note a singer has to reach.
Find a Target NoteKey to key distance in semitones
Choose two keys and the interval calculator shows how far apart they are, up and down. Counting C minor to A minor semitones gives 9 up or 3 down, so a song in C minor drops 3 semitones to sit in A minor. A minor to C major semitones come to 3 up, with the key signature unchanged, and F major to G minor semitones come to 2 up. You also see how many steps apart the keys sit on the circle of fifths and how many scale notes they share. Ready to move the music itself? Use the song key changer for audio or transpose sheet music for a score.
Compare Two KeysHear it melodic or harmonic
Play the two notes one after the other, as a melody would, or together, as a harmony would. Used as an interval identifier for ear training, the interval calculator lets you name what you hear, then check the readout. As an interval finder, music students use it to match each interval to a song they know.
Play an IntervalSemitone Chart: Every Interval From 0 to 12 Semitones
The whole octave measured up from C, with the name, the short form and the pure ratio the interval calculator reports for each step.
What you are looking at
An octave is 12 semitones, and every step has a name. What interval is 5 semitones? A perfect fourth, C to F. What interval is 8 semitones? A minor sixth, C to A flat, or an augmented fifth when it is spelled C to G sharp. Six semitones is the tritone, written as an augmented fourth or a diminished fifth depending on the letters. In the interval calculator above, the interval chart starts from whatever first note you pick, within an octave or compound, with the consonance of each step.
Interval Calculator Quick Answers for Common Note Pairs
The pairs people look up most, as the interval calculator measures them: upward from the first note, each with its inversion. The two interval numbers always add up to 9 and the semitones to 12.
| Going up from the first note | Flipped (the inversion) | |
|---|---|---|
| B to F interval | Diminished fifth, 6 semitones | F to B interval: augmented fourth, 6 semitones |
| D to F interval | Minor third, 3 semitones | F to D interval: major sixth, 9 semitones |
| E to G interval | Minor third, 3 semitones | G to E interval: major sixth, 9 semitones |
| A to C interval | Minor third, 3 semitones | C to A interval: major sixth, 9 semitones |
| G to B flat interval | Minor third, 3 semitones | B flat to G interval: major sixth, 9 semitones |
| C to E interval | Major third, 4 semitones | E to C interval: minor sixth, 8 semitones |
| G to B interval | Major third, 4 semitones | B to G interval: minor sixth, 8 semitones |
| F to A interval | Major third, 4 semitones | A to F interval: minor sixth, 8 semitones |
| D to G interval | Perfect fourth, 5 semitones | G to D interval: perfect fifth, 7 semitones |
| C to G interval | Perfect fifth, 7 semitones | G to C interval: perfect fourth, 5 semitones |
| D to A interval | Perfect fifth, 7 semitones | A to D interval: perfect fourth, 5 semitones |
| D to B interval | Major sixth, 9 semitones | B to D interval: minor third, 3 semitones |
Interval Calculator vs a Semitone Calculator vs Counting Keys
Counting keys on a piano gets you a number. Here is what else you need, and where each method stops.
| This siteToMIDI | Basic semitone calculator | Counting on a keyboard | |
|---|---|---|---|
| Semitones | Yes | Yes | Yes, slowly |
| Interval name and quality | Spelled from the letters you chose | Often one name per semitone count | Only if you know the rules |
| Cents and ratio | Yes | No | No |
| Inversion and compound form | Yes | No | By working it out |
| Note plus interval | Yes | Sometimes | By counting up |
| Key to key distance | Yes | No | By counting up |
| Hear it | Melodic and harmonic | Sometimes | Yes |
Who Uses an Interval Calculator
An interval calculator is for anyone who needs the distance between two notes, named and counted, without the finger counting.
Singers
Use the semitone calculator to work out how far to move a song so it fits your range, then hear the leap before you sing it. The pitch detector checks the note you actually hit.
Guitarists and bassists
One fret is one semitone, so the semitone count is the number of frets to move. Use it to plan a capo position or a bass line that walks between chords.
Composers and arrangers
Spell harmony lines correctly and transpose parts for B flat and E flat instruments without a single wrong accidental.
Producers
Pitch a sample or a vocal by the right number of semitones, and use cents to fine-tune layers. To get the notes of a recording first, use our audio to MIDI converter.
Ear trainers
Hear an interval, name it, then let the interval identifier confirm. Pair it with the circle of fifths to hear how the keys are related.
Interval Calculator FAQ
Quick, exact answers to the interval questions people ask most.
What is an interval calculator?
It is a tool that names the distance between two notes. Give the interval calculator two notes and it returns the interval name and quality, the number of semitones and the inversion; this one adds cents, the pure ratio, the compound form and playback.
How do I calculate the interval between two notes?
Count the letter names from the first note to the second, both included, for the number, then count the semitones for the quality. C to A is a sixth with 9 semitones, which makes it a major sixth. Or pick the two notes above and read the answer.
How many semitones are in an octave?
An octave has 12 semitones, the twelve keys, white and black, from one C to the next. Each semitone is 100 cents in equal temperament, so an octave is 1,200 cents. The interval calculator counts past the octave too.
What interval is 9 semitones?
Nine semitones is a major sixth, such as C up to A, when it uses the sixth letter name. Spelled with the seventh letter, as in C to B double flat, it is a diminished seventh. The semitone chart above lists every count from 0 to 12.
How many semitones from E to A?
Five going up: the E to A interval is a perfect fourth. Going down from E to the A below it is seven semitones, a perfect fifth. The semitone calculator above counts any pair the same way.
What is the difference between major, minor and perfect intervals?
Unisons, fourths, fifths and octaves are perfect; seconds, thirds, sixths and sevenths come in major and minor versions, the minor one a semitone smaller. Stretch any interval by a semitone past major or perfect and it becomes augmented; shrink it past minor or perfect and it becomes diminished.
Why are C to F sharp and C to G flat different intervals?
Both are 6 semitones, but C to F sharp spans four letter names (C, D, E, F), so it is an augmented fourth, while C to G flat spans five, so it is a diminished fifth. The interval calculator keeps your spelling and names the interval to match.
How do I find the inversion of an interval?
Subtract the number from 9 and the semitones from 12, and swap major with minor and augmented with diminished; perfect stays perfect. A major second inverts to a minor seventh, 2 semitones to 10. The interval calculator shows the inversion next to every result.
What is a compound interval?
Any interval wider than an octave. Add 7 to the number and 12 to the semitones: a major second plus an octave is a major ninth, 14 semitones. The interval calculator gives the compound form of every simple interval.
How many semitones is C minor to A minor?
A minor is 3 semitones below C minor, or 9 above it. C minor to D minor semitones come to 2 up, and A major to A minor semitones come to zero: the tonic stays put and only the key signature changes, from three sharps to none.
What key does C major -2 semitones become?
B flat major. Two semitones down from C is B flat, a major second below, and the key signature goes from no flats to two.
What do the cents and the ratio mean?
Cents measure size on the equal-tempered scale a piano uses, 100 per semitone. The ratio is the pure interval, the one a choir or a string quartet tunes to by ear: 3:2 for a fifth, 5:4 for a major third.
Can I hear the interval?
Yes. Play it melodic, one note then the other, or harmonic, both together. Using the interval calculator as an interval identifier, guessing before you look, is the fastest route to recognising intervals by ear.
Is this music interval calculator free?
Yes, with no account and no limits. It runs in your browser on a computer, tablet or phone, and nothing you enter is sent anywhere.
Can it name the chord my notes make?
The interval calculator works with two notes. For three or more, the chord finder names the chord, its inversion and the interval of each note above the root.
More Theory Tools Beside the Interval Calculator
Put the Interval Calculator to Work
Move a song, a score or a single note by exactly the right amount.
- Song Key ChangerShift a song up or down by semitones.
- Transpose Sheet MusicMove a score to any key or instrument.
- Online MIDI EditorFix notes in a piano roll and export.
- Song to Piano NotesGet piano notes and sheet music for a song.
- Online MetronomeA steady click with accents and tap tempo.
- MIDI to Sheet MusicTurn a MIDI file into printable notation.
Ready to Measure an Interval?
Pick two notes in the interval calculator above to get the name, semitones, cents and ratio, then hear it played. Free, exact and right in your browser.