Gauge is the string's diameter. A .010 string is 0.010" thick, and sets are named by their thinnest and thickest strings.
Ways to find out:
- Measure: use a caliper on a clean, straight section away from the bridge. Measure the high E and low E first.
- Check the maker's specs: many manufacturers list factory string gauges for each model. Your guitar may have been restrung since.
- Old packaging: if you or a shop kept it.
- Ask a shop: many will measure for you.
On wound strings, measure the full outside diameter including the wrap. Readings may vary by a thousandth or so between tools.
Once you know the gauges, you can match them or adjust. Bass players should also confirm scale length before ordering, since length matters as much as gauge. Our Power Wound Nickel collection lists every set's individual gauges for comparison.