Interval Practice Generator

What this generator does

Produces a set of interval questions with verified answers. Every question is constructed rather than looked up: the tool builds the upper note from the lower one and the requested interval, then reads the interval back off the finished pair and discards it unless the two agree. That round trip is what catches the cases a lookup table gets wrong — an interval that would need a triple sharp to spell, or a compound interval whose letter arithmetic and semitone arithmetic disagree.

How to use this tool

1. Choose what kind of question you want — name the interval, write the note, or invert it.
2. Choose a difficulty. Starter uses white notes only; advanced adds double accidentals and intervals larger than an octave.
3. Set how many questions you want.
4. Press Generate, work through them, then reveal the answers.

Understanding the controls

Question type

Naming asks you to identify the interval between two written notes. Building asks you to write the note a stated interval above one. Inverting asks for the interval you get by turning it upside down. They test genuinely different things — naming is reading, building is writing, inverting is the rule of nine.

Difficulty

Starter uses naturals only and only major, minor and perfect intervals within an octave. Standard adds sharps and flats. Advanced adds double accidentals, augmented and diminished qualities, and compound intervals up to a 15th — which is where the spelling starts to matter most.

Number of questions

Up to forty. A worksheet of twelve is about right for a lesson; forty is a revision session. Every question in a set is generated independently, so the same interval can appear twice — which is realistic rather than a fault.

Seed

Makes the set reproducible, so a teacher can print the same worksheet for a whole class or reprint one that has been lost.

Worked examples

Naming

E♭ up to G — a major 3rd. Four semitones and three letter names, E-F-G.

The pair that catches people

C to F♯ is an augmented 4th; C to G♭ is a diminished 5th. Six semitones either way, and different answers.

Building

A perfect 5th above B is F♯, not F. B to F is a diminished 5th, which is a semitone smaller.

Inverting

A major 3rd inverts to a minor 6th: 3 + 6 = 9, and major becomes minor.

Common use cases

• Grade-exam theory practice, where intervals are marked on their spelling
• A teacher printing a different worksheet for each student in a group lesson
• Warming up before a sight-singing or aural session
• Self-testing before a music-college entrance test
• Building the habit of reading interval names off a score rather than counting frets

How this generator works

An interval has two parts and they are worked out separately. The number comes from the distance between the letter names alone — C to any kind of E is a third, whatever accidentals are involved, because C, D, E is three letters. The quality then comes from comparing the actual semitone distance with what that number would be in its natural form: a third made of four semitones is major, three semitones is minor, five is augmented. Deciding the number before the quality is exactly the discipline that makes the site's scale generator spell F major with a B♭, and it is why this can distinguish intervals that sound identical. Inversion follows the rule of nine — the two numbers add to nine and the quality flips, with perfect staying perfect — and the tool checks that rule against a re-derivation from the actual notes rather than trusting it.

Randomness and fairness

The lower note, the interval number and the quality are drawn independently within whatever the difficulty allows, using the browser's cryptographic random number generator. Nothing about the answer is random — once the two notes exist the interval between them is a fact, and the tool derives it rather than remembering what it drew. A seed switches to a reproducible, non-cryptographic generator so the same worksheet can be printed twice; that mode is deliberately not cryptographically secure, which is what makes it reproducible.

For how randomness is produced across the whole site, see how Generate Random works.

Assumptions this tool makes

• Intervals are measured upwards from the first note to the second.
• The naming conventions are common-practice Western ones, which is what graded exams and most theory teaching use.

Limitations and good to know

• There is no audio. This tests interval spelling and naming on paper, which is a different skill from hearing an interval and recognising it.
• Notes are given as letter names rather than on a stave, so it does not test reading notation itself.
• The diminished unison is excluded. It falls out of the arithmetic and puts the upper note below the lower one, and theorists have argued about whether it exists for a century.
• Intervals larger than a 15th are not covered, because the names stop being used and nothing is taught above that.
• It cannot mark your answers — it gives you the correct ones to check against.

Common mistakes

Counting semitones and stopping there

Count the letter names first to get the number, then use the semitones to decide the quality. Four semitones is a major 3rd or a diminished 4th depending entirely on how the notes are written.

Counting the gaps between letters rather than the letters

C to E is a third because C, D and E are three letters — you count the notes, not the steps between them. This is why there is no such thing as a zeroth.

Assuming every number can be major or minor

Unisons, fourths, fifths and octaves are perfect, never major or minor. Only seconds, thirds, sixths and sevenths take major and minor.

Inverting by counting to eight

It is nine, not eight — a third inverts to a sixth. The number you started on is counted at both ends, which is where the extra one comes from.

Practical tips

• Do a set of naming questions and then the same set as building questions. Recognising an interval and writing one are different skills and most people are much better at the first.
• When an answer surprises you, write both notes on a stave before deciding the tool is wrong. Almost every disagreement is a letter miscounted.
• Start at standard rather than starter unless you are teaching a beginner — white notes only removes exactly the cases that make intervals worth practising.

Troubleshooting

The same interval appeared twice in one set

Questions are drawn independently, so repeats happen. Over twelve questions a repeat is more likely than not — that is what independent draws look like, and preventing it would make the set less random rather than more.

An answer uses a double flat

That is correct rather than a fault, and only appears at advanced difficulty. A diminished 4th above C♭ genuinely needs one. Drop to standard if you do not want them.

Privacy and your data

Nothing is entered and nothing is stored. Questions are generated in your browser, no worksheet is uploaded or written into the page address, and analytics records only that the tool was used along with the question type and difficulty — never a question or an answer.

Frequently asked questions

Why is C to F♯ not the same as C to G♭?

They sound the same and they are different intervals. C to F♯ spans four letter names (C, D, E, F) so it is a fourth, and six semitones makes it augmented. C to G♭ spans five letters so it is a fifth, and six semitones makes that diminished. Which one is correct depends on the key and on what the music is doing next — and an exam marks it.

What does inverting an interval mean?

Move the lower note up an octave, so it becomes the upper one. A major 3rd from C up to E inverts to a minor 6th from E up to C. The numbers always add to nine and the quality flips: major to minor, augmented to diminished, and perfect stays perfect.

Which intervals are consonant?

By the common-practice convention, unisons, fourths, fifths and octaves are perfect consonances, major and minor thirds and sixths are imperfect consonances, and everything else is a dissonance. That is a description of how Western tonal theory classified them, not a claim about what sounds good — which depends on context, style and taste.

Can I use this for a graded theory exam?

Yes, for the written interval questions, which are marked on spelling exactly as this tool treats them. It will not help with the aural components, which need sound.

Why are some questions impossible to spell?

They are not offered. Where an interval would need a triple sharp or triple flat above a particular note the tool discards it rather than printing something unwritable. That is a real limit of notation rather than of the tool.