Best lightweight cordless string trimmer

Every trimmer roundup ranks runtime and swath. Neither of those is what makes people put the tool down. This is the only yard tool held at full arm extension for the whole session, and the published weights span 80%.

The short answer

The published weights

1. Greenworks ST80L210 — the lightest published

7.1 lb bare, a 16 inch swath, a published 6200 RPM motor speed that neither competitor discloses, a 30-minute recharge that is the fastest in our registry, and a four-year battery warranty.

It is also efficient: 160Wh over 45 published minutes is about 3.56 watt-hours a minute, effectively identical to the Ryobi despite a pack a third smaller. The catch is the 0.080 in line, which its own specification positions as a lighter-duty gauge. For lawn edges and light growth that is fine; for a neglected fence line it is not.

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

2. EGO ST1521S — light where it matters, on paper

EGO does not publish a weight for this configuration, which is a genuine gap, but two published details point the right way: a carbon fiber shaft and a small 2.5Ah kit pack, which at 140Wh is the lightest battery of the three tools here.

The POWERLOAD head is the fatigue feature nobody counts. Reloading line by threading a spool is the job everyone hates and the one that happens at the worst moment; a head that winds it at the push of a button removes it entirely. Add a five-year tool warranty and a published lifetime warranty on the shaft.

The published cost is runtime: 140Wh at about 4.67 watt-hours a minute is 30 minutes, the shortest here. Fitting a larger EGO pack fixes the runtime and adds the weight back.

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

3. Ryobi RY402110 — the honest heavyweight

We include it because it is the tool most likely to be the right buy despite losing this page's criterion. Sixty-seven published minutes, an adjustable 15 to 17 inch swath and 0.095 in line make it the best long-session trimmer we hold specs for.

And it is 12.9 lb loaded on a 72.25 inch shaft, which is a lot of leverage. If your trimming is twenty minutes of lawn edges, buy something lighter. If it is an hour of rough boundary, the weight buys you a tool that will still be cutting at the end.

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

Reducing the weight you actually carry

1. Fit the smallest pack that finishes the job. Work out your minutes and multiply by the tool's draw — about 3.6 watt-hours a minute on the Ryobi and Greenworks, 4.7 on the EGO.
2. Use a strap if the tool accepts one. It moves load off your wrists onto your shoulders, which is where it belongs.
3. Work the tip of the line. Burying the head in growth loads the motor and makes you fight the tool.
4. Split the session. Two twenty-minute passes with a pack change in between are easier than forty continuous minutes, and cost the same energy.
5. Consider an attachment system. If a power head already lives in the shed, the 8 in edger attachment is a different, lighter tool for the edging half of the job.

#ad Check the EGO Power+ 8" Edger Attachment EA0800 price on Amazon — how we're funded.

What we cannot tell you

Two of three manufacturers publish no loaded weight and one publishes no weight at all, so the comparison above is incomplete through no fault of ours. Balance matters as much as mass on a shafted tool and nobody publishes that either.

What is published: 7.1 lb bare at the light end, 12.9 lb loaded at the heavy end, and a line-gauge split that tracks almost exactly with the weight difference.