What string gauges do I need for a 7-string, 8-string or drop tuning?

Common tunings, lowest string first

The lowest string is where gauge matters most. These are the standard names.

Drop D

D A D G B E. Standard six-string tuning with the low E dropped a whole step.

Drop C

C G C F A D. Every string down a whole step, and the lowest down one more.

7-string standard

B E A D G B E. A low B under standard six-string tuning.

Drop A on a 7-string

A E A D G B E. The low B dropped a whole step.

8-string standard

F# B E A D G B E. A low F# under 7-string standard.

Pick your gauges in six steps

1. 01Write down your tuning and scale lengthNote the pitch of every string and your scale length: the vibrating length from the nut to the saddle. Measure from the nut to the 12th fret and double it, or check the maker’s spec. On a multiscale guitar each string has its own length, longest on the low side.
2. 02Start from a set made for itString makers sell 7-string and 8-string sets, and heavier sets for drop tunings. Start there, then swap single strings if the calculator shows one out of line with the rest.
3. 03Go heavier as you tune lowerTuning a string down a whole step cuts its tension by about 20% at the same gauge and scale length. A common rule of thumb: for each whole step you tune down, try the next heavier set, for example 10s to 11s. Then confirm it in a calculator.
4. 04Check the tension in a calculatorMany string makers publish tension charts or an online tension calculator. Enter each gauge, the note it tunes to, and your scale length. Compare the result with a set that already feels right on your guitar, and aim for low strings that feel about as firm as the rest.
5. 05Check the fit before you string upA much heavier string may not sit in a nut slot cut for a thinner one, or pass through the tuner post or the bridge. Check the lowest strings first.
6. 06Set the guitar up for the new setNew tension moves the neck and the intonation. Check the nut slots, neck relief, string height and intonation, in that order, or book a setup. The next section covers each one.

Why lower tunings need heavier strings

A string’s tension depends on three things: its pitch, its scale length and its mass. Tune it lower and the tension drops. Tension rises with the square of the scale length, so a few extra inches add up: going from a 25.5-inch to a 27-inch scale adds roughly 12% at the same pitch and gauge. A thicker, heavier string brings the tension back.

Too little tension shows up fast. The low strings feel floppy, buzz against the frets, and go sharp for a moment when you pick hard.

Set up after a gauge change

Nut slots

A slot too narrow for the new string pinches it. You hear a ping as you tune, and the string sticks sharp or flat after a bend. A tech widens the slot; a little pencil graphite in the slot helps in the meantime.

Neck relief

More tension pulls the neck into more forward bow, and less lets it straighten. Check the relief and adjust the truss rod a quarter turn at a time. The fret buzz guide shows how to measure it.

String height

Once the relief settles, check the action and raise or lower the saddles to suit how hard you play.

Intonation

Compare the 12th-fret harmonic with the fretted note at the 12th fret. Fretted note sharp: move the saddle back, away from the neck. Flat: move it toward the neck. Heavier strings usually need the saddle further back.

Floating bridge

On a floating tremolo, more string tension tilts the bridge forward. Tighten the spring claw screws in the back cavity until the bridge sits level again, then retune and check it once more.

Common mistakes

• Keeping the same set after tuning down. The low strings go floppy, buzz, and go sharp when you dig in.
• Judging a set by gauge alone. The same gauge feels tighter on a longer scale, so check the tension for your scale length.
• Forcing a heavy string into a narrow nut slot. It binds, pings and drifts out of tune after bends. Have the slot widened.
• Filing nut slots without the right files. A slot cut too deep buzzes on the open string and means a new nut.
• Skipping the intonation check after a gauge change. Chords up the neck drift out of tune.
• Cranking the truss rod in big turns to match the new tension. A quarter turn at a time, then let the neck settle.

Words used here

Gauge

String thickness in thousandths of an inch. A set called 10s has a .010-inch high E.

Tension

How hard a string pulls when it is tuned to pitch. More tension feels firmer under the pick.

Scale length

The vibrating length of a string, from the nut to the saddle. Roughly twice the distance from the nut to the 12th fret.

Extended-range guitar

A guitar with more than six strings, usually a 7 or 8-string, with the extra strings below the low E.

Drop tuning

Tuning only the lowest string down a whole step, so one finger across the bottom three strings plays a power chord.

Multiscale

Fanned frets: each string has its own scale length, longer on the low side, where extra tension helps most.

Nut binding

A string catching in a nut slot that is too narrow or rough. It pings as you tune and sticks out of pitch after bends.

Neck relief

The slight forward bow in a neck that gives the strings room to vibrate. Set with the truss rod.

Intonation

Whether notes up the neck stay in tune with the open strings. Set by the saddle positions.

Related guides

• Is it fret buzz or electrical hum?The unplugged test, then action, relief and frets in order.→
• Why does my high-gain rig hiss, and where does the noise gate go?Hiss and hum at high gain: find the source, then place and set the gate.→