Cordless Trimmer Line: Matching Gauge to Voltage

Battery voltage is a decent proxy for how much line a trimmer can swing.

18V–20V

Stick to 0.065” (0.080” max). These motors don’t have the torque to spin heavy line, and over-gauging kills runtime and feed.

24V–40V

0.080” is the sweet spot; 0.095” for tougher jobs if the head allows. Most homeowner work lives here.

56V–80V & gas

0.095” and up. These have the torque for weeds and light brush — under-gauging just wastes their capability.

Mismatch symptoms

Too heavy: motor bogs, line won’t feed, runtime tanks. Too light: line snaps constantly and cuts poorly in anything but soft grass.

Match the gauge to your head’s rating first, then to the job. Find line and spools for your exact model on the brand pages.