Frequently Asked Questions

Music theory is the study of how music works — the rules and patterns behind melody, harmony, and rhythm. Learning it helps you understand why certain notes and chords sound good together, makes it easier to learn new songs, and gives you the tools to write your own music. You don’t need to master every concept at once; even a basic understanding of scales and chords will make a noticeable difference in your playing.

An interval is the distance in pitch between two notes. Intervals are measured in half steps (semitones) and named by their size: unison, second, third, fourth, fifth, sixth, seventh, and octave. Each interval has a distinct sound quality — for example, a perfect fifth sounds open and stable, while a minor second sounds tense. Understanding intervals is essential because they are the building blocks of both scales and chords.

A scale is an ordered set of notes following a specific interval pattern (such as whole-whole-half-whole-whole-whole-half for the major scale). A key refers to the tonal centre of a piece of music and the group of notes that belong to it. For example, the key of C major uses the notes of the C major scale, but “key” also implies harmony, chord relationships, and a sense of resolution to the tonic note. In short, a scale is a pattern; a key is the musical context built around that pattern.

A key signature appears at the beginning of a staff and tells you which notes are sharp or flat throughout the piece. Sharps and flats follow a fixed order: sharps appear as F♯, C♯, G♯, D♯, A♯, E♯, B♯, while flats go B♭, E♭, A♭, D♭, G♭, C♭, F♭. For sharp keys, the last sharp is one half step below the tonic; for flat keys, the second-to-last flat is the tonic. No sharps or flats means C major (or A minor).

Diatonic means “belonging to the scale.” When something is described as diatonic, it uses only the seven notes of a particular major or minor scale with no added sharps or flats. Diatonic chords, for example, are built by stacking thirds using only notes from the current scale. The Interactive Chord Finder shows you every diatonic chord for whichever scale you select, making it easy to see which chords naturally fit together.

A scale is a sequence of notes arranged in ascending or descending order according to a fixed pattern of intervals. The most familiar example is the major scale, which follows a whole-whole-half-whole-whole-whole-half step pattern. Scales give melodies and harmonies their character — a major scale sounds bright and happy, while a minor scale sounds darker and more melancholic. Every piece of tonal music is rooted in one or more scales.

The core difference is in the third degree of the scale. A major scale has a major third (four half steps from the root), giving it a bright, uplifting sound. A natural minor scale has a minor third (three half steps), producing a darker, more sombre character. The interval patterns are also different: major is W-W-H-W-W-W-H, while natural minor is W-H-W-W-H-W-W. There are also harmonic and melodic minor variants that raise the sixth or seventh degrees for smoother voice leading.

Modes are scales derived by starting on a different degree of a parent scale. The seven modes of the major scale are Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian. Each mode uses the same set of notes as the parent scale but has a different tonic, giving it a unique interval pattern and mood. For example, D Dorian uses the same notes as C major but centres on D, creating a minor sound with a raised sixth. The Interactive Chord Finder lets you explore all seven modes and see their diatonic chords.

That depends on how you count them. Mathematically, there are 2,048 possible combinations of notes within a twelve-tone octave, but only a fraction are musically practical. Western music commonly uses around 20–30 scales, including major, natural/harmonic/melodic minor, pentatonic, blues, whole-tone, diminished, and the seven modes. Many global musical traditions add dozens more. The Interactive Chord Finder covers the most commonly used scales and modes so you can explore their sound and harmony.

The pentatonic scale is a five-note scale that omits the two most dissonant intervals found in the major scale (the fourth and seventh degrees in the major pentatonic). This makes it extremely versatile and pleasant-sounding — almost any combination of pentatonic notes works well together. The major pentatonic (1-2-3-5-6) sounds bright and folk-like, while the minor pentatonic (1-♭3-4-5-♭7) is the backbone of blues, rock, and pop soloing. It’s often the first scale beginners learn for improvisation.

A chord is three or more notes sounded together. The most basic chord is a triad, which consists of a root, a third, and a fifth. The quality of the third and fifth determines the chord type: major triads have a major third and perfect fifth, minor triads have a minor third and perfect fifth, diminished triads have a minor third and diminished fifth, and augmented triads have a major third and augmented fifth. Chords provide the harmonic foundation of music.

A triad is a three-note chord built by stacking two thirds (root, third, fifth). A seventh chord adds one more third on top, creating a four-note chord (root, third, fifth, seventh). The added seventh introduces extra colour and tension. Common seventh chord types include major seventh (warm and jazzy), dominant seventh (tense, wants to resolve), minor seventh (mellow and smooth), and half-diminished seventh (dark and unstable). The Interactive Chord Finder displays both triads and seventh chords for every scale degree.

Chords are built by selecting a starting note (the root) from the scale and then stacking every other note above it. For a triad, you take the first, third, and fifth degrees counting from the root. For a seventh chord, you add the seventh. Because each scale degree sits at a different position in the interval pattern, you get different chord qualities on each degree. In C major, for instance, the I chord is C major, the ii is D minor, the iii is E minor, and so on. This process is called harmonising a scale.

Roman numerals represent chords by their position (degree) within a scale rather than by a specific note name. This makes it easy to transpose progressions to any key. Upper-case numerals (I, IV, V) indicate major chords, while lower-case numerals (ii, iii, vi) indicate minor chords. A degree sign (°) marks diminished, and a plus sign (+) marks augmented. For example, the popular I–V–vi–IV progression in C major is C–G–Am–F, but in G major it becomes G–D–Em–C.

Extended chords go beyond the seventh by continuing to stack thirds. A ninth chord adds the ninth (which is the second note an octave up), an eleventh chord adds the ninth and eleventh, and a thirteenth chord adds the ninth, eleventh, and thirteenth. In practice, musicians often omit some inner notes to keep the voicing clean. Extended chords are widely used in jazz, neo-soul, R&B, and modern pop to add richness and sophistication to harmony.

A chord inversion rearranges the notes of a chord so that a note other than the root is in the bass (lowest position). A triad in root position has the root at the bottom; first inversion puts the third in the bass; second inversion puts the fifth in the bass. Seventh chords also have a third inversion with the seventh in the bass. Inversions create smoother voice leading between chords and add harmonic variety without changing the underlying chord quality.

At the top of the chord finder you’ll see 12 buttons representing the chromatic notes (C, C♯/D♭, D, and so on). Click or tap any note to set it as the root key. The entire interface updates instantly — the piano keyboard, scale notes, step pattern, and diatonic chord table all reflect your chosen root. Notes that have common enharmonic spellings (like C♯ and D♭) are shown together on the same button.

Below the key selector you’ll find a row of quick-access pills for the most popular scales (Major, Natural Minor, Pentatonic, Blues, etc.). Click any pill to select that scale. For the full list, click “More Scales” to open a searchable dropdown with over 60 scales organised into categories like Diatonic Modes, Pentatonic, Jazz, World, and more. Type in the search box to filter by name. The colour scheme of the interface changes to reflect the character of the selected scale.

The two-octave piano keyboard displays your selected scale visually. Notes that belong to the scale are marked with coloured circles showing their note name, while non-scale keys remain unlit. Click or tap any key to hear it — the app uses the Web Audio API so no plugins are needed. When you click a chord in the table below, the chord’s notes light up on the keyboard so you can see the voicing. During step pattern or sequencer playback, the keyboard highlights each note or chord as it plays.

The Step Pattern section shows the interval structure of your selected scale as a row of circles connected by lines. Each circle displays a scale degree note, and the labels between them show the step size: W (whole step), H (half step), m3 (minor third), or larger intervals for exotic scales. Click “Play Scale” to hear the notes played ascending with an LED glow effect that follows the sequence. You can also click any individual note circle to hear that note and see it highlighted on the piano. This section is collapsible — click the heading to expand or collapse it.

The Chord Sequencer lets you build and play chord progressions. Add chords by clicking the “+” button on any chord in the table below, or by dragging chords into the sequencer strip on desktop. You can also add rest slots for silence. Each slot has a duration picker (1, 2, 4, 8, or 16 beats) and a delete button. Drag slots to reorder them. Set the tempo (BPM) and time signature, then press Play to hear your progression. The piano keyboard highlights each chord as it plays. Toggle the loop button to repeat the progression continuously. If you change the scale, stale chords show an amber dot — press “Update” to refresh them to the new scale.

The Chord Types section contains toggle cards for each chord extension: Triad (3 notes), Seventh (4 notes), Ninth (5 notes), Eleventh (6 notes), and Thirteenth (7 notes). Each card shows the note count and formula (for example, “Root + 3rd + 5th” for triads). Click a card to show or hide that chord type’s column in the diatonic chords table. Triads and sevenths are enabled by default. This section is collapsible.

The table shows every diatonic chord built from the current scale. Each row represents a scale degree (I through VII), and columns show different chord extensions (triads, sevenths, ninths, etc.) depending on which Chord Type toggles are active. Each chord cell displays the chord name (like Cmaj7), its Roman numeral (I), the chord quality (like “Major”), and the individual note names. Click any chord to hear it and see its notes highlighted on the piano keyboard. On desktop, you can drag chords directly into the sequencer; on mobile, use the “+” button instead.

Yes. The Step Pattern, Chord Sequencer, Chord Types, Diatonic Chords, and Transpose sections are all collapsible. Click or tap the section heading (with its triangle indicator) to toggle between expanded and collapsed views. Collapsing a section hides its content but does not stop playback — if the sequencer is playing, it continues even when collapsed. This is useful for focusing on the parts of the interface you need while keeping the screen uncluttered.

The Chord Practice tool is a timed drilling exercise for chord recognition. It presents diatonic chords one at a time and gives you a set number of beats to identify or play each chord before the next one appears. It tracks your score and lets you retry missed chords at the end of each session.

Scale mode generates chords from a specific key and scale you choose (for example, C Major or D Dorian). This is ideal for learning which chords belong to a particular scale. Random Chords mode picks chords of the selected types from all 12 keys, with a configurable count (5–100 chords). This is better for general chord recognition practice across multiple keys.

The Tempo & Timing section lets you set the BPM (30–240), time signature (2/4, 3/4, 4/4, 5/4, or 6/8), and how many beats each chord gets before the next one appears (1, 2, 4, or 8 beats). A metronome toggle provides an audible click on each beat. A good starting point is 60 BPM with 4 beats per chord, which gives you four seconds to respond.

Yes. If you connect a MIDI keyboard via USB, the tool detects it automatically through the Web MIDI API (supported in Chrome, Edge, and other Chromium-based browsers). During a session, play the chord on your keyboard and the tool matches your notes against the expected chord in real time. It uses pitch-class matching, so any octave or inversion is accepted — you just need the right set of notes. Your MIDI keyboard also produces piano sound as you play. If MIDI permission is blocked, a retry button appears to request access again.

Yes. All practice settings — mode, chord types, tempo, display options, and chord count — are saved in your browser and persist between sessions. The root key and scale selection are also shared with the homepage chord finder, so changing the key on one page automatically updates the other when you navigate between them.

After a session ends, the score summary shows how many chords you got correct, wrong, and skipped. If any were missed, a “Practice Missed” button appears. Clicking it starts a new session containing only the chords you got wrong or skipped. This simple form of spaced repetition concentrates your effort on the chords that need the most work.

Transposition means shifting all the notes and chords of a piece up or down by a fixed interval, so the music sounds in a different key while keeping the same relationships between notes. This is essential when writing parts for transposing instruments (like trumpet or saxophone), when a singer needs a song in a higher or lower key, or when using a guitar capo. The interval between the original and new key is measured in semitones.

A transposing instrument is one where the written note differs from the sounding (concert) pitch. For example, when a B♭ trumpet plays a written C, the sounding pitch is actually B♭ — two semitones lower. This exists for historical and ergonomic reasons: players can use the same fingerings across instrument families. Common transposing instruments include B♭ trumpet, B♭ clarinet, E♭ alto sax, F French horn, and A clarinet. Non-transposing instruments like piano, guitar, flute, and violin are called “C concert pitch” instruments.

A capo raises the pitch of all strings by the number of frets it covers. Each fret equals one semitone. To find which chord shapes to play with a capo, you need to subtract the capo value from the desired key. For example, if you want to play in E♭ Major with a capo on fret 3, subtract 3 semitones from E♭ to get C — so you play C Major chord shapes and the capo raises them to E♭. In the Transpose section, simply select your target key at the top, click a capo button (1–5), and the mapping tables show you exactly which shapes to use.

Yes. Set FROM to the instrument the part is written for, and TO to the instrument that needs to play it. For example, if an alto sax part is in A Major and a trumpet player needs to read it, set FROM to E♭ and TO to B♭. The app calculates the combined offset and shows the trumpet part in D Major. This works for any combination of the seven instrument groups. You don’t need to convert to concert pitch first — the tool handles the math directly.

Click the PDF button next to the scale heading (for example, “C Major (Ionian)”). This opens the export dialog where you can choose what to include and how it should look. You can also press Ctrl+P (or &Cmd;+P on Mac) to open the export dialog directly.

Yes. The PDF is generated entirely in your browser — no data is sent to a server. The PDF library is loaded on demand the first time you export, so it is available offline once cached. If you have installed the app as a PWA, PDF export works without an internet connection.