Look at almost any folk or country guitarist's gig bag and you'll find a capo tucked in a side pocket. It's a small, inexpensive tool, but it opens up a genuinely useful set of options for how you play. Here's what it does and how to use one.

What a capo actually does

A capo clamps across all the strings at a chosen fret, effectively creating a new "nut" at that point and raising the pitch of every open string by a fixed amount. Put a capo on the 2nd fret, for example, and your open chords now sound two semitones higher, without you having to change a single finger shape.

Why players use one

• Changing key without changing chord shapes. If a song sits comfortably in the key of G but a singer needs it a few steps higher, a capo lets you keep playing the same familiar open shapes while the actual pitch shifts to match.
• Getting a brighter, more open tone. Capoing higher up the neck naturally produces a lighter, chimier sound than playing the same chord shapes down at the nut, which is a big part of the classic, ringing sound heard across so much folk and country recording.
• Playing with other musicians. If you're jamming with someone playing in a different key, a capo can let you both use familiar shapes while landing on the same actual pitch.

Types of capo

Spring-loaded, quick-clamp capos are the most common and fastest to use, simply squeeze and clip on. Screw-adjustable capos let you fine-tune the clamping pressure, which some players prefer for more consistent tuning across different neck shapes and string gauges. There are also partial capos, which only cover some strings, used for more specialised open-tuning-style effects.

A quick tip on tuning

Always check your tuning again after placing a capo, since clamping pressure can very slightly pull certain strings sharp, particularly with a spring-loaded capo applied a bit too firmly. A quality capo with even pressure across the neck minimises this, but it's worth a quick check regardless.

Where to put it

There's no single correct fret, it depends entirely on what key you're trying to reach and what shapes you want to play. Experimenting with a capo at different frets is a genuinely fun way to discover new voicings and textures on chords you already know well.