Music Theory Interval Calculator

Measure interval names, semitones, ratios, and cents accurately. Compare notes across octaves with clear outputs. Save practical results for lessons, tuning, and physics analysis.

Calculator

Formula used

MIDI pitch number: MIDI = (octave + 1) × 12 + pitch class.

Frequency from note: f = A4 × 2^((MIDI - 69) / 12).

Equal interval ratio: ratio = 2^(cents / 1200).

Interval cents: cents = semitones × 100 + cent offset.

Measured deviation: deviation = 1200 × log2(measured frequency / target frequency).

How to use this calculator

Choose a start note and octave. Then choose the end note and octave. Select a direction mode if you want an ascending, descending, or absolute interval. Enter the A4 tuning value. Use 440 for standard concert pitch. Add a cent offset when testing microtonal tuning or pitch correction. Enter a measured frequency if you want a tuning comparison. Press the calculate button. The result appears above the form.

Example data table

Start End Interval Semitones Cents Approx ratio
C4 G4 Perfect fifth 7 700 1.498307
A4 C5 Minor third 3 300 1.189207
E4 E5 Octave 12 1200 2.000000

Music Intervals and Physical Sound

A musical interval is the distance between two pitches. It is also a physical relationship between two vibration rates. When the calculator compares two notes, it first converts each note to a numbered pitch. That makes the interval easy to measure. The result shows semitones, cents, ratio, and frequency change. These values help musicians and science students see the same sound from two useful angles.

Why intervals matter

Intervals shape melody, harmony, tuning, and chord color. A perfect fifth feels stable because its frequency relationship is close to a simple ratio. A minor second sounds tense because the pitches sit very close together. In equal tuning, each semitone is spaced by the twelfth root of two. This system lets music move through every key with predictable spacing.

Using physics with theory

Frequency explains the size of an interval. If A4 is set to 440 Hz, every other note can be calculated from that standard. Moving up one semitone multiplies frequency by 2^(1/12). Moving down one semitone divides by the same value. Cents give a finer unit. One semitone equals 100 cents. This is useful for tuning checks, ear training, instrument setup, and acoustics.

Reading the results

The interval name gives a musical label. The semitone count gives a chromatic distance. The cents value gives exact equal-tempered distance. The ratio shows how the target frequency relates to the starting frequency. A ratio above one means the target is higher. A ratio below one means the target is lower. The measured frequency box can compare a real sound against the calculated target. It reports whether the sound is sharp or flat.

Practical uses

Use this tool before arranging, composing, teaching, or tuning. It can check a melody jump. It can compare a singer's pitch to a target. It can help explain why octave doubling repeats the same note name. It also supports physics lessons about waves. The export buttons make a small record for reports, practice notes, or class work.

Because the form keeps both theory and frequency visible, it suits mixed lessons. Students can test enharmonic spellings, octave shifts, and pitch standards. Teachers can export examples and review them later. The workflow stays simple and clear.

FAQs

What is a music interval?

A music interval is the pitch distance between two notes. It can be described by name, semitones, cents, or frequency ratio.

Why does the calculator use cents?

Cents are small tuning units. One equal-tempered semitone equals 100 cents. They help show fine pitch differences clearly.

What does the ratio mean?

The ratio compares target frequency to starting frequency. A ratio of 2 means the target pitch is one octave higher.

What is A4 reference frequency?

A4 reference frequency sets the tuning standard. Many musicians use 440 Hz, but orchestras and recordings may use other values.

What does force ascending do?

Force ascending treats the interval as upward. If the chosen end note is lower, it moves the interval into a higher octave.

Can this calculator check tuning?

Yes. Enter a measured frequency. The calculator compares it with the target and shows sharp or flat deviation in cents.

Does spelling affect the interval?

This tool focuses on pitch distance. Enharmonic notes, such as C# and Db, share the same pitch class in equal tuning.

Can I export the result?

Yes. Use the CSV button for spreadsheet data. Use the PDF button for a simple printable summary.

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