The Ultimate Guide to Guitar Keys

It’s hard not to admire a guitarist who can simply improvise along with any given song. And often, these players simply need to ask what key the song is in! A lot of guitar instruction doesn’t spend much time focusing on guitar keys. But understanding the fundamentals of different keys and how they work is a crucial part of becoming a competent musician. This guide will help you understand guitar keys and improve your musicianship.

What are Guitar Keys?

If you listen to a lot of live music, you’ve probably heard a guitarist or instrumentalist tell another band member what key the next song is in. And while most of us have at least heard of musical keys, plenty of people don’t know what a “key” actually is.

A simple (yet surprisingly accurate!) definition of a key is a group of chords or notes that sound good together. If you write your own songs but don’t know any music theory, you may find that your songs still sound very good. But if you take a look at the chords or notes you use, you’ll probably find that they’re in the same key.

But if you want to grow as a guitarist, it can be very helpful to understand what notes and what chords make up different keys.

Notes

The key notes guitar players learn are easier to remember than you might think. That’s because lots of lead guitarists use movable scale shapes to play up and down the neck.

If you want to play individual notes in a given guitar key, it’s a good idea to have some basic familiarity with a guitar scale or two. The minor pentatonic scale is a great one to start with, as it helps you find the keys on guitar neck quickly and easily.

Knowing your scale shapes will let you quickly play the notes in a given key, but it’s also wise to have at least a basic understanding of what notes can be found in what keys.

The Chromatic Scale

Let’s start from the beginning. In Western music, there are 12 notes. Each is a half step (one fret on the fretboard) higher than the next. Here are all 12:

• A
• A#/Bb
• B
• C
• C#/Db
• D
• D#/Eb
• E
• F
• F#/Gb
• G
• G#/Ab

If you’ve started learning scales, you might have started with the chromatic scale. The concept of a chromatic scale is easy enough; it’s simply the 12 notes in order. The key of the scale is determined by the root note, which in this case is the first one in the scale. So if you played the above bulleted list in order, you would be playing the A chromatic scale.

For many guitarists, learning the chromatic scale starts on one string guitar riffs. If you wanted to play the A chromatic scale, you could start on the 5th string (playing it open) and then move down the fretboard a note at a time.

Though the chromatic scale is a useful introduction to scales in general, it doesn’t lend itself well to the creation of actual music. Most guitar keys you can play in are based on diatonic scales, which are based around seven notes. These scales are made up of notes that tend to sound good together.

Diatonic Scales

The chromatic scale only contains half steps, but diatonic scales are made up of both whole and half steps. Whole steps are two frets apart on the fretboard. Let’s look at major and minor diatonic scales.

As you may already know, major scales (like major chords) tend to have an upbeat, “happy” sound. In a major scale, the step pattern is whole step/whole step/half step/whole step/whole step/whole step/half step, or WWHWWWH.

To really understand how this works, let’s devise the A major scale from the A chromatic scale mentioned above. Here’s the A chromatic scale:

A A#/Bb B C C#/Db D D#/Eb E F F#/Gb G G#/Ab

Remember that there is a half step between each note. So if you start with A and follow the WWHWWWH pattern, you get this:

A B C#/Db D E F#/Gb G#

That’s the A major scale!

If you want to play a minor scale, it’s good to know that the pattern of steps is different. For a minor scale, the step pattern is whole step/half step/whole step/whole step/half step/whole step/whole step, or WHWWHWW. So if you look again at the A chromatic scale and follow that pattern, you get the A minor scale:

A B C D E F G

Remember that, in the case of both major and minor scales, the scale is named after the first note, or the root note. So any time you play a major or minor scale, the first note you play will tell you the name of the scale.

Chords

Whether you want to learn to strum along in an acoustic guitar key or want to develop some elaborate fingerpicking pattern to go along with a given song, knowing the chords in a key is similarly important. The theory behind this portion is a little bit more complex, but it’s well worth understanding.

Guitar chords are based on diatonic scales like the ones we discussed above. Each chord is based on a triad, which is a set of three notes from the relevant diatonic scale:

• The root — the first note in the scale
• The third — the third note in the scale
• The fifth — the fifth note in the scale

Major Chords

If you are playing a major chord, the root, third, and fifth are the exact notes from the major scale. So going off the examples above, an A major chord contains the notes A, C#, and E. This combination results in the bright, energetic sound that most major chords have.

If you’re a hands-on learner, you can easily see this pattern when you play an open A major on your guitar:

• 1st string — open (E)
• 2nd string — 2nd fret (C#)
• 3rd string — 2nd fret (A)
• 4th string — 2nd fret (E)
• 5th string — open (A)
• 6th string — muted

Though you play five strings, you’re only playing three different notes.

Minor Chords

We all know that minor chords have a somewhat darker, sadder sound. That’s because the third note is flattened by a half step. As we mentioned above, the third in an A major chord is C#. So we lower that to a C, and the notes in an A minor chord are A, C, and E.

You probably know that to play an open A minor, you just fret the second string at the first fret instead of the second. That changes the C# to a C, so you’re now playing A, C, and E — the notes in an A minor chord.

Diminished Chords

If you’re somewhat new to guitar, you may not be familiar with diminished chords. These chords have a dark, dissonant sound. They aren’t a type of chord you’d want to use all the time, but in moderation, they can add foreboding energy to any song.

That energy comes from the fact that diminished chords have both a flattened third and a flattened fifth. So the notes in A diminished would be A, C, and D# (or Eb). The Adim chord is a bit trickier to play, but here’s one way to do it:

• 1st string — muted
• 2nd string — 13th fret (C)
• 3rd string — 14th fret (A)
• 4th string — 13th fret (D#)
• 5th string — 12th fret (A)
• 6th string — muted

Again, you can see that the chord is made up of just the three notes — A, C, and D#.

Identify the Chords of a Key

If you want to play rhythm guitar in different keys on guitar, understanding which chords go with each key is a must. Some keys on guitar are easier to master than others.

Luckily, though it may take some time to really master, there’s a formula for picking out the chords in a given key. Each key will have three major chords, three minor chords, and a diminished chord.

Each chord has its own Roman numeral. The numeral indicates its root note’s distance from the root note of the major scale itself. Major chords have uppercase Roman numerals, minor chords have lowercase Roman numerals, and diminished chords have lowercase Roman numerals followed by a degree sign (˚).

These numerals are based on the degrees of a major or minor scale. Though you don’t necessarily need to memorize the degrees of a scale to find the chords in a key, it can be helpful to know the names of the degrees:

• 1 — Tonic (root note)
• 2 — Supertonic
• 3 — Mediant
• 4 — Subdominant
• 5 — Dominant
• 6 — Submediant
• 7 — Subtonic

Identifying Chords in Major Keys

To devise what chords are in a major key, use this pattern of scale degrees:

• Major (I)
• Minor (ii)
• Minor (iii)
• Major (IV)
• Major (V)
• Minor (vi)
• Diminished (vii˚)

Of course, dominant seventh and minor seventh chords fit into keys as well. If a given major chord is part of a key, then the corresponding seventh is as well. So if you can play a G major in a given key, you can play a G7, too. If Gm is part of a key, you can play Gm7 as well.

Let’s find what chords are in the key of A major. As a reminder, here’s the A major scale: A B C#/Db D E F#/Gb G#

So applying the pattern, we get the following chords:

• I — A major
• ii — B minor
• iii — C#/Db minor
• IV — D major
• V — E major
• vi — F#/Gb minor
• vii˚ — G# diminished

Identifying Chords in Minor Keys

If you need to find the chords in a given minor key, follow this pattern of scale degrees:

• Minor (i)
• Diminished (ii˚)
• Major (III)
• Minor (iv)
• Minor (v)
• Major (VI)
• Major (VII)

Since we’re working with a minor key, we’ll need to find these chords using the A minor scale instead of the A major scale.

So looking at the A minor scale (A B C D E F G) and applying the pattern, we see that these are the chords in the key of A minor:

• i — A minor
• ii — B diminished
• III — C major
• iv — D minor
• v — E minor
• VI — F major
• VII — G major

Creating Chord Progressions

Have you ever seen someone write out a chord progression using Roman numerals like the ones mentioned above? Writing progressions this way helps you to quickly see how to play a song in any key.

For example, a very popular major key progression is I V vi IV. This is the progression used in “Let It Be” by the Beatles. If you were going through this progression in A major, you would play A, E, F#m, and D:

• I — A
• V — E
• vi — F#m
• IV — D

Let’s say you want to play this progression in C. The C major scale is C D E F G A B. Here are the chords within the scale:

• I — C
• ii — Dm
• iii — Em
• IV — F
• V — G
• vi — Am
• vii˚ — Bdim

So if we want the progression I V vi IV, we get this:

• I — C
• V — G
• vi — Am
• IV — F

So you would need to play C, G, Am, and F — a fairly common chord progression.

Common Chord Progressions

Whether you’re interested in songwriting or just want to know more about how chords in a given key can be used, understanding some common progressions and their applications can be extremely useful. Here are some often-seen progressions and examples of songs that use them:

I vi IV V

This one is sometimes called the “Heart and Soul” progression or the “50s Progression.” As you might guess, it’s the progression used in the famous piano duet “Heart and Soul.” You’ll also hear it in “Beautiful Girls” by Sean Kingston and “I Will Always Love You” by Dolly Parton (and made famous by Whitney Houston). It was used in Sam Cooke’s “Wonderful World” and in a whole host of Beatles songs, including “Octopus’s Garden,” “A Hard Day’s Night,” and “Please Mister Postman.”

vi IV I V (or i VI III VII)

The first version of this progression is sometimes called the “sensitive female chord progression,” as it’s been used in several thoughtful ballads performed by women. These include “One of Us” by Joan Osborne and “Behind These Hazel Eyes” by Kelly Clarkson. More broadly, both versions of this progression are often called the “pop-punk progression” even though they can be found in many genres. You can hear the progression in “21 Guns” by Green Day, “Zombie” by the Cranberries, and “Hello” by Adele.

I vi ii V

This one is kind of a more minor version of the “Heart and Soul progression.” It appears in “Fluorescent Adolescent” by the Arctic Monkeys, “Dancing in the Moonlight” by King Harvest, “Rainbow Connection” by the Muppets, and “What’s Going On” by Marvin Gaye.

Finding the Key of a Song

Being able to tell the key of a song based on its chord progression is an extremely useful skill. Some very experienced musicians can figure out the key just by listening, but taking a closer look at the chords to determine the key is a great first step.

In some cases, looking for a single dominant seventh chord will help you. This doesn’t usually work for blues songs, as a decent portion of the chords in any blues song will likely be dominant seventh chords.

If there’s a single dominant seventh chord in a song, it’s usually the V chord in a progression. The easiest way to find the key is to take a look at the circle of fifths. For example, let’s say a song has an A7 chord. To find the key, start with A simply move one chord counterclockwise on the circle of fifths. In this case, the song would likely be in the key of D.

Another way to fairly easily find the key is to take a look at the first and last chords in a progression. “Folsom Prison Blues” by Johnny Cash has an E A E B7 progression. For a song in the key of E major, you can find the chords E, F♯m, G♯m, A, B, C♯m, and D♯dim. This essentially includes all the chords in the song (if a song’s key includes a major chord, the dominant seventh of that chord is also included). So we can say that the song is in E major.

Of course, there are plenty of online applications that can help you find the key of a song based on its chords. If you want to test your skills, you can always find the key yourself and then use one of these applications to check for accuracy.

FAQs

Now that you have a little more knowledge of guitar keys and what they mean, you might have some questions as you go forward and learn. Here are some of the most common questions that guitarists ask:

Final Words

Learning about guitar keys and really mastering them takes time, so don’t worry if you’re still a little confused. Finding a guitar key chart for beginners and posting it where you practice can be especially helpful, as can different keys on guitar. In time, you’ll remember which chords are part of which keys and even be able to improvise riffs and leads along with nearly any song. It takes some time and effort, but it’s well worth it — you’ll play better and more confidently than ever before!

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