What to Look For

Voltage and power: 20V trimmers handle light grass. 40V covers most residential needs. 56V–80V competes with gas for thick weeds and long sessions.

Cutting swath: 12–13 inches for small yards, 14–16 inches for larger properties. A wider swath covers more ground per pass but weighs more.

Line feed: Bump-feed (tap the head on the ground) is simple and reliable. Automatic feed advances line as it wears. Both work — automatic is more convenient but slightly more complex to maintain.

Battery compatibility: If you already own cordless tools, buy into the same battery platform. EGO, Ryobi, and Milwaukee batteries cross-compatible within their families, saving hundreds on extra batteries.

Our Picks

Tested against typical residential trimming tasks — lawn edging, fence lines, and garden bed borders.

Trimmer Line Types and Feeding Systems

The cutting line matters nearly as much as the motor. Different line shapes and materials suit different trimming tasks, and understanding your feeding system saves frustration during use.

Line Shapes

Round line is the most common and works well for general grass trimming. It's smooth-cutting and inexpensive. Standard diameters for residential trimmers are .065 to .080 inches — check your trimmer's specifications before buying replacement spools.

Multi-sided line (square, star, pentagon) cuts more aggressively than round. The edges create a slicing action rather than tearing, producing cleaner cuts on thicker weeds and overgrown grass. It wears faster than round line but handles tougher vegetation more efficiently.

Serrated or twisted line combines aggressive cutting with reduced noise. The spiral shape cuts through dense material while creating less of the characteristic trimmer whine. A good compromise for suburban use where noise matters.

Feeding Systems Explained

Bump feed: Tap the trimmer head on the ground while running, and a mechanism advances a few inches of new line. Simple, reliable, and used on most residential trimmers. The only downside is you need to stop and bump when line runs short, which interrupts your flow.

Automatic feed: A centrifugal mechanism detects when line is short and advances new line automatically. More convenient than bump feed, but the mechanism is more complex and occasionally over-feeds, wasting line. Common on mid-range and premium trimmers.

Fixed line or rapid reload: Pre-cut line segments snap into the head — no spool winding required. EGO's rapid reload system is the best example: when line wears down, you stop, snap in new segments, and resume in seconds. This eliminates the most frustrating part of string trimmer ownership (winding a tangled spool).

Safety and Technique

Wear safety glasses and closed-toe shoes whenever you use a string trimmer. The line spins at several thousand RPM and throws debris — small rocks, bark fragments, and thorns — with surprising force. Long pants protect legs from the same projectiles.

For clean edging along beds, tilt the trimmer head vertically and walk slowly along the edge. For scalping overgrown areas, sweep in slow arcs, taking thin passes rather than plunging into thick growth. Forcing the trimmer into heavy material stalls the motor and breaks line faster than methodical passes.

Keep trimmer line away from tree trunks. The line easily cuts through bark, creating wounds that invite disease and insect damage. A circle of mulch around tree bases (no grass to trim) eliminates this risk entirely.