ChordLab is a chord calculator for modern four-part voice leading and in that a bit of a specialist tool. Everyone has heard these chords in the arrangements of Big Bands, the music of Debussy and other impressionists and of course many film scores. With ChordLab we can flip through all possible permutations of these voicings including the rarer ones. More theoretical background is available in the documentation. ChordLab is not a general chord app for beginning instrumentalists. To the intermediate player, however, ChordLab can be a source of great inspiration and introduction to many new color choices.

Four-Part Harmony

Four-part harmony may feel restrictive on instruments capable of more than 4 voices, but for a small choir for example it is a basic fact of life. It allows the arranger or accompanist to declutter the spectrum in a sense by playing fewer notes. Root and fifth substitutions are applied automatically when dialing up a chord in ChordLab. Once the quality of a chord has been set it can then be viewed and listened to in all standard and not so standard drop voicings and moved through its inversions. This is of particular importance to guitar players as quite a few voicings are impossible to play and one may be left with rather few options. Chord spelling is also the main feature of ChordLab's Apple Watch app.

Chord Spelling

Harmony is a difficult and complex part of music theory with chord spelling at its very basis. What is a chord? Is it C - E - G# or C - E - Ab? You like the sound of those four notes on your guitar, but is it a chord? And if so, what is it called? These are typical issues facing the creative musician when trying to bring a new song to paper. Music theory is often complex and correctly spelling a chord that may have sharps and flats, double flats or double sharps is not always easy. This is where the traditional chord books and apps become useless and ChordLab steps in. ChordLab involves the ear and showcases the finer shades of harmony available with each alteration, voicing and inversion based on the concepts of music theory. It is a great aid where chord spelling and voice leading are concerned but also delivers when a fingering for an unknown chord is needed.

Circle of Fifths

ChordLab has an interactive Circle of Fifths. With it we can look up key signatures for major and minor scales as well as all other modes derived of the major scale. So it is possible for example to display key signatures for all mixolydian scales and simultaneously highlight the other degrees for that mode. Additionally ChordLab displays degree structures for a key in standard Roman numerals. This is extremely useful when putting together chord progressions. Roots of the current harmonic domain are highlighted in white and can be tapped to audit the associated chords.

Finding Chords

The chord finder feature in ChordLab allows you to search its database for 3 or 4 note structures to determine their harmonic quality. To find a chord in its database ChordLab uses the enharmonically simplest solution and does not require you do know whether a note is called G# or an Ab. This is especially useful for guitarists that seldomly encounter chords in root position due to the tuning of the instrument.

Dark Mode

Tuning Presets

The guitar instrument has a tunings window. All common standard and open tunings as well as a custom setting are available from the tunings picker at the top of the window. Using any of the slider will override the current tuning and generate a custom tuning. Strings can be tuned by 7 semitones higher or lower than the standard tuning. Experimenting with tunings is a great way to find chord voicings that are not available in the standard tuning and thus expanding one's vocabulary.

Key Features

  • Chord spelling for all common chords
  • Notation and textual representation of chord tones
  • Chord finder for triads and seventh chords
  • Alto, bass, tenor, treble clefs, TAB and grand staff
  • All inversions and standard voicings
  • Virtual piano and guitar instruments
  • Chord tone labeling in instrument views
  • All common open and alternate tunings presets (guitar)
  • Automatic reduction to 3 or 4 voices
  • Automatic root and fifth substitution
  • Key signatures lookup (circle of fifths)


There is a lot of functionality built into ChordLab, but as with any tool it is what we make of it. If chord spelling is a term in your vocabulary ChordLab should be of interest because it does that automatically. Or maybe you want to grow your chord reportoire. Putting music theory into words often makes it sound overly complex yet nobody would say that red or blue are complicated. ChordLab lets you play and work with colors in a sense and shows you how to play them. It is very a unique tool for musicians, song-writers, professionals and music students and one that you will find yourself coming back to again and again.

Available for:


Apple Watch

ChordLab for Apple Watch is an extension of its iOS app that implements the chord spelling functionality of ChordLab. Just dial in your chord's root and qualifier (i.e. Fb maj7) and viola it shows you Fb, Ab, Cb and Eb as the chord tones (no B in this chord, my man).