What Is a Musical Interval?
A musical interval is the distance in pitch between two notes. It's measured in half steps (semitones) and named according to how many scale degrees it spans. Understanding intervals is crucial for ear training, composing, improvising, and analyzing music.
How Intervals Are Named
Intervals have two components:
- Number (quantity): how many staff positions it spans — 2nd, 3rd, 4th, etc.
- Quality: perfect, major, minor, augmented, or diminished
Perfect Intervals
Unison (0 semitones), Perfect 4th (5), Perfect 5th (7), and Octave (12) are called "perfect" because they sound completely consonant and stable. They have no major/minor distinction.
Major and Minor Intervals
2nds, 3rds, 6ths, and 7ths can be major or minor. Minor intervals are one semitone smaller than major intervals. For example: Major 3rd = 4 semitones; Minor 3rd = 3 semitones.
Augmented and Diminished
Adding a semitone to a perfect or major interval makes it augmented. Subtracting a semitone from a perfect or minor interval makes it diminished. The augmented 4th / diminished 5th (6 semitones) is called the tritone — historically the "devil in music" due to its dissonant sound.
All 12 Intervals with Reference Melodies
| Interval | Semitones | Reference Song |
|---|---|---|
| Unison | 0 | Same note repeated |
| Minor 2nd | 1 | Jaws theme |
| Major 2nd | 2 | Happy Birthday (first 2 notes) |
| Minor 3rd | 3 | Smoke on the Water |
| Major 3rd | 4 | When the Saints Go Marching In |
| Perfect 4th | 5 | Here Comes the Bride |
| Tritone | 6 | The Simpsons theme |
| Perfect 5th | 7 | Star Wars theme |
| Minor 6th | 8 | The Entertainer |
| Major 6th | 9 | My Bonnie Lies Over the Ocean |
| Minor 7th | 10 | Somewhere (West Side Story) |
| Major 7th | 11 | Take On Me (A-ha) |
| Octave | 12 | Over the Rainbow |
Consonance and Dissonance
Intervals range from completely stable (consonant) to very tense (dissonant):
- Most consonant: Unison, octave, perfect 5th, perfect 4th
- Moderately consonant: Major/minor 3rds and 6ths
- Most dissonant: Minor 2nd, major 7th, tritone
Dissonant intervals create tension that "wants" to resolve to a consonant interval — this is the engine of Western tonal harmony.
A Practical Ear Training Schedule
- Week 1–2: Perfect 5th and octave. These are the "purest" sounds.
- Week 3–4: Major and minor 3rd (the major/minor feel)
- Week 5–6: Perfect 4th and major 2nd
- Week 7–8: Minor 2nd, tritone, major 6th
- Week 9–12: All 12 intervals in random order
Train Intervals with BeMaestro
BeMaestro's Interval Training module presents intervals in random order and tracks exactly which ones give you trouble. The spaced repetition algorithm ensures you spend more time on weak spots. It's the most efficient way to master all 12 intervals.
Conclusion
Mastering intervals is the gateway to real musical fluency. Use the reference melody technique to build initial recognition, then drill with BeMaestro's interval module until every interval feels as obvious as the color red. Download BeMaestro and start training today!