Music & Entertainment

How to Transpose Chords: Learn How to Change Keys While Playing Music

Written by MasterClass

Apr 13, 2019 • 7 min read

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While performing a piece of music, a musician may want to play the composition in a different key than originally written. To do so, the performer will use a technique called transposition.

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What Is Transposition?

Transposition is the process by which a musician changes a composed piece of music from its original key to a different key. The musician will change each chord and each note to fit a new key, and the composition will either sound higher or lower than it originally did. A transposition could also involve going from a major key to a minor key (such as going from D major to D minor), or going from a tonal key to a mode (such as going from an F# minor scale to the F# Dorian mode).

2 Reasons Why a Musician Would Want to Transpose a Piece

There are many reasons why musicians choose to transpose, but they tend to fall into two categories.

  1. To make the music easier to perform. The number one reason musicians transpose is to make a piece easier to play. Let’s say you’re performing a song originally written for a male tenor vocalist, like “Sittin’ On the Dock of the Bay” by Otis Redding. Redding performed this song in the key of G, where the lowest sung note is a G3. Now, let’s say the lead singer of your cover band is a woman with an alto range. It’s going to be very difficult for her to sing that low G3. If she can even reach it, the note will barely be audible. One option would be to move the whole song up by an octave so that the low G3 becomes a G4. But then you run into an issue on the other end—the high notes may be too high and piercing. The solution is to transpose the song to a new key where both the low notes and the high notes fit comfortably into the alto range.
  2. To change the fundamental character of a song. Sometimes, a performer might want to put a unique stamp on a well-known song. Transposing from one type of key to another can make this possible. Imagine an upbeat song like “La Bamba” by Ritchie Valens, which is built entirely on major chords. Now imagine if every one of those major chords became a minor chord, with the melody slightly adjusting to fit the notes of the new key. This would be a bold take on the song and likely to stand out among the many hundreds of cover versions performed over the years.

How to Transpose a Melody

In order to transpose a piece of music, you need to think of its notes and chords in terms of “intervals.” And when it comes to melodies, you need to know a bit about scales and scale degrees. Here are the basics:

The fundamental building block of Western music is the major scale, and it consists of 7 notes. Starting from the lowest note, and going up, they are:

  • 1—the “root” of the scale
  • 2—a whole step up from the root
  • 3—a whole step up from the 2nd
  • 4—a half step up from the 3rd
  • 5—a whole step up from the 4th
  • 6—a whole step up from the 5th
  • 7—a whole step up from the 6th

Then, with one more half step, we get back to the “root”—only now we’re an octave higher than we were before.

The second most important building block of Western music is the natural minor scale. This is similar to a major scale, but with a few half steps where there were previously whole steps.

  • 1—the “root” of the scale
  • 2—a whole step up from the root
  • 3—a half step up from the 2nd
  • 4—a whole step up from the 3rd
  • 5—a whole step up from the 4th
  • 6—a half step up from the 5th
  • 7—a whole step up from the 6th

And then we need one final whole step to get back to the root—but again it’s an octave higher than where we began. In a natural minor scale, we often call the 3rd, 6th, and 7th degrees as “flat degrees.” Therefore, we might say that the notes of a minor scale are:

1 - 2 - b3 - 4 - 5 - b6 - b7

When you transpose a melody, focus on what “scale degrees” each of the original notes is. As an example, let’s take the song “Free Fallin’” by Tom Petty & the Heartbreakers.

  • Petty’s original recording is in the key of F major
  • The notes of that scale are F - G - A - Bb - C - D - E
  • This means that F is the first scale degree (or “root”), G is the 2nd, A is the 3rd, Bb is the 4th, and so on

The first four notes of Petty’s vocal melody—“She’s a good girl”—are F - G - A - F. However if we have our transposing hat on, we must think of those as scale degrees. In other words, the notes are 1 - 2 - 3 - 1.

Now let’s transpose this melody to the key of Db major.

  • The notes in a Db major scale are Db - Eb - F - Gb - Ab - Bb - C
  • We are preserving the 1 - 2 - 3 - 1 melody
  • Therefore, the first four notes of the transposed version are Db - Eb - F - Db

By thinking in terms of intervals, you can transpose to any key, so long as you know which notes belong in which scale.

How to Transpose Chords

Transposing a chord progression is very similar to transposing a melody. Only this time instead of thinking of scale degrees, we need to think of Roman numeral notation. Here’s how it works:

The major scale has a series of “triads” (three note chords containing a root, a third, and a fifth) that are built upon the notes within the scale. We notate them using Roman numerals, as follows:

  • I—a major triad starting on the 1st degree of the scale
  • ii—a minor triad starting on the 2nd degree of the scale
  • iii—a minor triad starting on the 3nd degree of the scale
  • IV—a major triad starting on the 4th degree of the scale
  • V—a major triad starting on the 5th degree of the scale
  • vi—a minor triad starting on the 6th degree of the scale
  • viiº—a diminished triad starting on the 7th degree of the scale

When we assign these Roman numerals to specific keys, we get a specific set of chords. For instance, let’s take F major, the key of that Tom Petty song. The chords associated with that scale are:

  • F major (the I)
  • G minor (the ii)
  • A minor (the iii)
  • Bb major (the IV)
  • C major (the V)
  • D minor (the vi)
  • E diminished (the viiº)

In “Free Fallin’,” the primary progression is:
F Bb | Bb F C |

In Roman numeral notation, this would be analyzed as:
I IV | IV I V |

So if we were to transpose the song to, for instance, the key of B, we would utilize the I, IV, and V chords of that particular key. And the song would be played:

B E | E B F# |

So if a band wishes to cover “Free Fallin’” but their singer doesn’t have the same vocal range as Tom Petty, the band can use this Roman numeral system to transpose to a key where the melody suits their singer.

How to Transpose Chords in the Minor Scale

If you’re working in the natural minor scale, take note that these are the chords associated with that scale:

  • i—a minor triad starting on the 1st degree of the scale
  • iiº—a diminished triad starting on the 2nd degree of the scale
  • bIII—a major triad starting on the 3rd degree of the scale (which we sometimes call the flat third degree)
  • iv—a minor triad starting on the 4th degree of the scale
  • V—a major triad starting on the 5th degree of the scale
  • bVI—a major triad starting on the 6th degree of the scale (which we sometimes call the flat sixth degree)
  • bVII—a major triad starting on the 7th degree of the scale (which we sometimes call the flat seventh degree)

All of the same principles apply to minor key transposition as do to major key transposition. Once you understand how chords function in this Roman numeral system, all keys are available to you and your band!