Best string trimmer for a large yard

On a small lot any cordless trimmer finishes the job. On an acre of fence line, bed edge and around a dozen trees, the tool stops and the afternoon stops with it. Runtime is the specification that decides this category, and the spread between these four is larger than any other difference between them.

The short answer

Runtime spread against swath spread

It is worth putting the two numbers next to each other, because the marketing emphasizes the wrong one.

Four trimmers on published figures

1. RYOBI RY402110 — the runtime pick

Sixty-seven published minutes on 240Wh, an adjustable 15 to 17 inch swath, a carbon fiber shaft and 0.095 in bump-feed line. On a large property that is the combination: the widest swath here when you want it, narrowed to 15 inches when you are working close to a fence post, and the battery to keep going.

At 3.58Wh per minute it is also the most efficient trimmer in our registry by a hair — essentially tied with the Greenworks ST80L210's 3.56, and 23% better than the EGO's 4.67.

The cost is weight. At 12.9 lb with the 6.0Ah pack fitted it is the heaviest trimmer here loaded, and that pack is where the runtime comes from. An hour of trimming at that weight is real work.

#ad Check the Ryobi 40V HP Whisper 17" Carbon Fiber RY402110 price on Amazon — how we're funded.

2. Greenworks 2123802 — one powerhead, three attachment systems

Fifty published minutes on 200Wh, a 14 to 16 inch adjustable path, and compatibility with Poulan Pro, RYOBI Expand-It and TrimmerPlus attachments. That last line is why it ranks second on a large property rather than third.

A big lot needs edging, pole pruning and often brush cutting as well as trimming. Three attachments on one powerhead is three fewer batteries, three fewer chargers and one tool to store — see multi-head attachment systems.

Greenworks publishes more than most here: weight, battery watt-hours, runtime, line gauges and a four-year warranty on both tool and battery. What it does not publish is shaft material or a recharge time.

#ad Check the Greenworks 80V 16" Attachment-Capable String Trimmer (2123802) price on Amazon — how we're funded.

3. Greenworks ST80L210 — lightest, and fastest to recharge

Seven point one pounds without the battery, 45 published minutes, and a 30 minute recharge — the fastest in our registry. On a large yard that changes the arithmetic: with two packs, the spare is full again before the first is empty.

Against it: 0.080 in line is the thinnest here and will not last as long in heavy growth, and at 160Wh it ships the smallest battery of the four.

#ad Check the Greenworks 80V 16" String Trimmer ST80L210 price on Amazon — how we're funded.

4. EGO ST1521S — the best tool, the wrong kit for this job

POWERLOAD automatic line winding, a carbon fiber split shaft with a lifetime warranty on it, a five-year tool warranty and 0.095 in dual-feed spiral line. As a trimmer this is the nicest of the four to use.

It is last here for one reason: the kit ships a 56V 2.5Ah pack, which is 140Wh and 30 published minutes. On a large property that is one battery change too many. On the EGO platform, with a 7.5Ah or 10.0Ah pack you already own, the picture changes entirely.

#ad Check the EGO Power+ 15" POWERLOAD Carbon Fiber ST1521S price on Amazon — how we're funded.

On a big property, the line runs out too

Runtime is not the only consumable. Heavier line lasts longer against fence wire and brick edges, and 0.095 in is the heavier gauge here — our trimmer line guide covers the trade against motor load. For genuinely heavy growth, a brush cutter attachment does what no string head can.

What we cannot tell you

We have not timed these trimmers. Every runtime here is the manufacturer's own claim, measured on their own terms and almost certainly at low speed in light grass — nobody publishes the test conditions. EGO publishes no weight for the ST1521S and neither Greenworks page publishes shaft material. No maker publishes linear feet of trimming per charge, which is the figure a large-yard buyer would actually want.