liminfoInterval Reference
Free web tool: Interval Reference
| Interval | Abbr | Semitones | Ratio | Example | Quality |
|---|---|---|---|---|---|
| Unison | P1 | 0 | 1:1 | C - C | Perfect Consonance |
| Minor 2nd | m2 | 1 | 16:15 | C - C# | Dissonance |
| Major 2nd | M2 | 2 | 9:8 | C - D | Dissonance |
| Minor 3rd | m3 | 3 | 6:5 | C - Eb | Imperfect Consonance |
| Major 3rd | M3 | 4 | 5:4 | C - E | Imperfect Consonance |
| Perfect 4th | P4 | 5 | 4:3 | C - F | Perfect Consonance |
| Tritone | A4 | 6 | 45:32 | C - F# | Dissonance |
| Perfect 5th | P5 | 7 | 3:2 | C - G | Perfect Consonance |
| Minor 6th | m6 | 8 | 8:5 | C - Ab | Imperfect Consonance |
| Major 6th | M6 | 9 | 5:3 | C - A | Imperfect Consonance |
| Minor 7th | m7 | 10 | 16:9 | C - Bb | Dissonance |
| Major 7th | M7 | 11 | 15:8 | C - B | Dissonance |
| Octave | P8 | 12 | 2:1 | C - C' | Perfect Consonance |
About Interval Reference
The Music Interval Reference is a searchable, filterable chart covering all 13 standard intervals used in Western music theory, from the Unison (P1) to the Octave (P8). For each interval, the table shows the full name, standard abbreviation (e.g., M3 for Major 3rd), semitone count, just intonation frequency ratio, a concrete note example from C, and the acoustic quality classification: Perfect Consonance, Imperfect Consonance, or Dissonance. This gives musicians, composers, and students a single reference for both the mathematical and perceptual properties of every interval.
Understanding intervals is foundational to music theory, chord construction, melody writing, and ear training. Perfect intervals (Unison, Perfect 4th, Perfect 5th, Octave) have frequency ratios of small integers (1:1, 4:3, 3:2, 2:1) and are perceived as highly stable. Imperfect consonances (Minor 3rd, Major 3rd, Minor 6th, Major 6th) form the basis of triads and are perceived as pleasant but not as stable as perfect intervals. Dissonances (Minor 2nd, Major 2nd, Tritone, Minor 7th, Major 7th) create tension and drive harmonic motion in tonal music.
The reference runs entirely in your browser with no server calls. You can filter the full table by quality category (All, Perfect Consonance, Imperfect Consonance, Dissonance) or search by interval name or abbreviation. The tool is useful for music students doing ear training, composers checking interval properties, and teachers preparing instructional materials.
Key Features
- Complete chart of all 13 Western music intervals from Unison (P1, 0 semitones) to Octave (P8, 12 semitones)
- Frequency ratios in just intonation (e.g., Perfect 5th = 3:2, Major 3rd = 5:4) for each interval
- Acoustic quality classification — Perfect Consonance, Imperfect Consonance, and Dissonance — with color-coded badges
- Concrete note examples for each interval measured from C (e.g., Minor 3rd: C to Eb)
- Real-time search by interval name or abbreviation (e.g., search "M3" or "tritone")
- Filter by quality category to focus on consonances or dissonances only
- Standard interval abbreviations (P1, m2, M2, m3, M3, P4, A4, P5, m6, M6, m7, M7, P8)
- Bilingual Korean/English interface with dark mode support and responsive table layout
Frequently Asked Questions
What is a music interval?
A music interval is the distance in pitch between two notes, measured in semitones (half steps). Intervals are named by their size (e.g., 2nd, 3rd, 5th) and quality (Perfect, Major, Minor, Augmented, or Diminished). For example, the interval from C to G is a Perfect 5th, spanning 7 semitones, with a frequency ratio of 3:2 in just intonation.
What is the difference between Perfect, Major, and Minor intervals?
Perfect intervals (Unison, 4th, 5th, Octave) are unique in that they have only one quality form in a standard scale. Major and Minor intervals come in pairs — a Major 2nd (2 semitones) and a Minor 2nd (1 semitone), for example. Reducing a Major interval by one semitone gives a Minor interval. Reducing a Perfect or Minor interval by one semitone gives a Diminished interval.
What is the Tritone and why is it called dissonant?
The Tritone (augmented 4th, abbreviated A4) spans exactly 6 semitones — exactly halfway through the octave. Its just intonation ratio of 45:32 involves large numbers, indicating a complex frequency relationship. This produces acoustic beats and a sense of tension that the ear perceives as unstable. In medieval music theory it was called "diabolus in musica" (the devil in music). In tonal harmony, it typically resolves to a consonance.
What does the frequency ratio tell me?
The frequency ratio expresses the relationship between the frequencies of the two pitches in just intonation. Simpler ratios (1:1, 2:1, 3:2) correspond to acoustically smooth, consonant sounds because the overtone series of the two notes align more closely. More complex ratios (45:32, 16:15) produce more acoustic beating and are perceived as dissonant or tense.
How are intervals used in chord construction?
Chords are built by stacking intervals above a root note. A major triad stacks a Major 3rd (M3, 4 semitones) and then a Minor 3rd (m3, 3 semitones) above the root — e.g., C–E–G. A minor triad reverses this: Minor 3rd then Major 3rd — e.g., C–Eb–G. Seventh chords add another 3rd on top. Understanding interval qualities and semitone counts is essential for building and analyzing any chord.
What is ear training and how does this reference help?
Ear training (solfège/aural skills) involves learning to recognize intervals by sound without seeing the notation. This reference helps by providing a single lookup for the name, abbreviation, semitone count, and note example of every interval. Many ear training methods associate each interval with a well-known song — for example, a Perfect 5th sounds like the Star Wars theme. This chart gives the factual properties to complement that practice.
Why does the Tritone not convert to ISBN-10?
This is a music interval reference, not an ISBN tool. The Tritone (A4) is the augmented 4th interval spanning 6 semitones between C and F#. It is classified as Dissonant due to its complex 45:32 frequency ratio. It has historically been considered the most tension-filled interval in Western tonal harmony and plays a key role in dominant 7th chords and blues music.
Is this tool useful for guitar, piano, and other instruments?
Yes. Intervals are an instrument-agnostic concept in music theory — they apply equally to piano, guitar, violin, voice, and any other instrument. On a guitar, intervals correspond directly to fret distances on the same string. On a piano, they correspond to key distances. This reference is useful for any musician studying or applying music theory regardless of their instrument.