Trimmer line is sold by diameter. The three sizes you'll see most on home trimmers are .065 in, .080 in and .095 in. Picking the right one matters more than picking the thickest.
The common sizes
| Diameter | Metric | Typical use |
|---|---|---|
| .065 in | 1.65 mm | Light cordless and corded trimmers, lawn edges and grass |
| .080 in | 2.0 mm | Mid-size cordless and gas trimmers, thicker grass and light weeds |
| .095 in | 2.4 mm | Higher-powered gas and 40V–80V trimmers, dense weeds and brush |
Why thicker isn't always better
Every trimmer is designed for a specific line diameter. Line that's thicker than recommended adds drag on the motor, drains batteries faster, and often won't feed through an auto-feed head at all. Line that's thinner than recommended wears and breaks quickly. Use the diameter listed in your trimmer's manual or printed on the head.
If you use pre-wound auto-feed spools, the diameter is already matched to your trimmer — just make sure the spool is listed for your model.
Spool, pre-cut line or bulk line?
- Pre-wound spools are the quickest option for auto-feed heads: drop in and go.
- Pre-cut lines are used by heads that take individual pieces of line instead of a spool (some Ryobi and EGO heads, for example). They come in bundles cut to the right length.
- Bulk line is the cheapest per foot, but you'll need to wind it onto the spool yourself.
Round, twisted or square?
Round line is the most durable and feeds most reliably, which is why it's the default for auto-feed spools. Twisted and shaped lines cut more aggressively and can be quieter, but they wear faster against hard surfaces.
Keeping line fresh
Nylon line dries out and gets brittle when it's stored in heat or sunlight for a long time. Keep spare spools and line in a cool, shaded place, and use older stock first.
Check your model number before orderingEvery product page lists the brands and model numbers it fits. Not sure? Ask us.
