Updated October 9, 2026.
Weed eater string sizes in inches and millimeters
Use this chart to narrow the diameter, then check your trimmer and installed head manuals. Job descriptions are starting points, not permission to fit a larger line. Metric values below are rounded conversions; packaging may use a nearby nominal size.
| Diameter | Metric | Typical job | Compatibility check |
|---|---|---|---|
| .065 in. | 1.65 mm | Light lawn grass | Small heads and light-duty tools only when specified |
| .080 in. | 2.03 mm | Maintained lawn edges | A common light-duty option; check the head |
| .095 in. | 2.41 mm | Regular weeds and fence lines | Common on gas and larger battery models |
| .105 in. | 2.67 mm | Heavier grass and weeds | Only if both tool and head support it |
| .130 in. | 3.30 mm | Demanding growth with a compatible setup | Not a universal upgrade for stock heads |
.080 inch line
This is fine for lighter grass and smaller battery trimmers. I would not choose it as the main line for thick commercial trimming unless the tool is clearly built around lighter work.
.095 inch line
This is the practical sweet spot for many commercial straight-shaft trimmers. It handles regular weeds and fence lines without overloading most pro gas models.
- Good default for weekly maintenance and heavier yard work.
- Works well on many ECHO, Husqvarna, Shindaiwa, and battery pro-style trimmers.
- Still check the manual before forcing heavier line into a head.
.105 inch and heavier line
Heavier line is useful in rougher growth, but only when the trimmer has enough torque and the head supports it. On weaker battery tools, heavy line can hurt runtime and cutting speed.
Round, twisted, square, or serrated?
Round line is easy to feed and forgiving. Twisted line can be quieter. Square and serrated lines bite harder but may wear faster and load the tool more. For most buyers, size and feed reliability matter more than exotic shape.
Check the exact model, not just the brand
Milwaukee specifies .080, .095 and .105-inch line for the 3006-22 dual-battery trimmer. ECHO lists .095-inch line on the SRM-2620T. Those specifications do not mean every Milwaukee or ECHO head accepts the same diameters. A replacement head can also change the allowed line and loading length.
- Check diameter, shape and loading length in the installed head's instructions.
- Stop the tool before inspecting or reloading, following the manual's isolation instructions.
- If heavier line feeds poorly or slows cutting, return to the recommended diameter rather than removing the guard.
Why thicker string is not always better
A larger diameter changes the load and leaves less room on a spool of fixed size. If your current line breaks, first check contact with masonry, worn eyelets, incorrect winding and brittle old line. A compatible fresh spool may solve the problem without moving to a larger diameter. String line is not a substitute for the approved blade setup when the job is woody brush.
Sources and compatibility
- ECHO trimmer and line selection catalog: Line categories and model specifications; use the current manual for final compatibility.
- Milwaukee 3006-22 specifications: Manufacturer-listed .080, .095 and .105-inch line sizes.
Find the size your manual specifies
Match diameter, shape and head compatibility before ordering. These links open Amazon search results, not a guaranteed fit for your trimmer.
- .080-inch trimmer line
For compatible heads used on maintained lawn edges.
Compare on Amazon - .095-inch trimmer line
A common size for regular weeds; confirm your model first.
Compare on Amazon - .105-inch trimmer line
For heavier growth only on tools and heads rated for this diameter.
Compare on Amazon
Next steps