An orange spool of round trimmer line and a coil of green line on a wooden bench next to a string trimmer head, with a lawn blurred behind

Yard tools

String trimmer line size chart

4 sources

Buy links on this page go through our /go/ redirects to the manufacturer or retailer. We earn nothing from them today; that may change. Disclosure.

Quick answer

The right trimmer line size is the one your trimmer head is approved for. STIHL sells its round line in .065, .080, .095, .105 and .130 inch, but says not all diameters are approved for all STIHL trimmers. Check your owner's manual or the instruction card for your trimmer head for the right diameter and length.

Trimmer line (Oregon Gatorline range):

Oregon Gatorline round, square and twist

Common diameters

The diameters STIHL lists for its Premium Round Line, with metric equivalents.

Inch	Millimeter (converted)	STIHL's mowing line guide for that range
.065 in	1.65 mm	Short grass, small gardens (1.4–2.7 mm)
.080 in	2.03 mm	Short grass, small gardens (1.4–2.7 mm)
.095 in	2.41 mm	Where small-garden and tall-grass ranges overlap (2.4 mm)
.105 in	2.67 mm	Tall grass, large gardens (2.4–3.3 mm)
.130 in	3.30 mm	Tall grass and overgrowth (up to 4.0 mm)

What heads take: examples from STIHL's chart

STIHL's selection chart lists a standard and optional diameter for each head. A few examples:

AutoCut C 5-2: .080 standard.
AutoCut C 6-2: .080 standard, .095 optional.
AutoCut C 26-2: .095 standard, .105 optional.
TrimCut C 52-2: .105.

Other brands publish their own figures in the manual. For the most common choice, see .080 vs .095.

Is trimmer line universal?

Partly. STIHL says its Premium Round Line fits all STIHL and competitive trimmer heads, but diameter still has to match what the head is approved for. Shape matters too. See round vs square.

Guides in this section

Guide.080 vs .095 lineHow the two most common sizes compare, and how to check what your head takes.Read guide

Fix guideLine keeps breakingThe causes trimmer makers list, in the order to check them.Read guide

GuideRound vs square lineWhat each trimmer line shape is for, from Oregon and STIHL.Read guide

Wrong size breaks line. Echo, Husqvarna and Ryobi all list the wrong diameter as a cause of line breaking. See line keeps breaking.

How we work: sizes come from STIHL's line guide, chart and mowing line sheet, and Oregon's FAQ. We don't test trimmer line ourselves. Sources are listed below.

Questions people ask

What size trimmer line do I need?

The diameter your trimmer head is approved for. STIHL says not all diameters are approved for all trimmers and to check the manual or the head's instruction card.

Is string trimmer line universal?

Partly. STIHL says its Premium Round Line fits STIHL and competitive heads, but the diameter must still match what your head is approved for.

What sizes does trimmer line come in?

STIHL's round line comes in .065, .080, .095, .105 and .130 inch.

Sources

Last checked Oct 23, 2026. Sizes come from STIHL; shapes from Oregon and STIHL; breakage causes from Echo, Husqvarna and Ryobi. Stop the engine or remove the battery before opening the head.