The Best Cordless String Trimmers

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Mowing makes a lawn look tidy. Trimming makes it look finished. A string trimmer handles the edges along fences, beds, trees and the driveway, which is where most yards look scruffy.

Cordless trimmers have caught up with small gas models for home use. The bigger question now is how the head feeds and reloads line, because that’s what annoys people most over time.

I look after my own lawn with EGO battery tools, and I work with tools and blades in my workshop. I have not tested every trimmer below. These picks are based on the published specs and owner reviews.

The picks

1. EGO 16″ LINE IQ with POWERLOAD (ST1623T): best overall

EGO lists a 16-inch cutting swath, 0.095-inch twisted dual-strand line, a brushless motor, a two-speed selector and a telescopic carbon fiber shaft, per EGO’s product page. The ST1623T kit includes a 56V 4.0Ah battery and charger and quotes up to 60 minutes. The tool-only version is the ST1620T.

Two features set it apart:

• LINE IQ feeds line automatically as it wears, so you never bump the head.
• POWERLOAD winds new line into the head when you press a button.

EGO gives a 5-year tool warranty, a 3-year battery warranty and a lifetime warranty on the carbon fiber shaft if you register within 90 days.

A long review by James Chambers praised the cutting power and the auto feed around obstacles. He noted that POWERLOAD takes a couple of tries to learn, that the line halves need to be even or you waste line, and that grass can build up in the head.

Why it’s the pick:

• No bumping and no hand-winding spools.
• Long runtime on the included battery.
• Shares batteries with EGO mowers and blowers.

What to watch: it costs more than basic trimmers, and the head needs an occasional clean-out. EGO’s own page showed “Coming Soon” when I checked, while dealers had it listed, so availability may vary.

2. Ryobi 40V HP Brushless Whisper Series 17″ (RY402011BTL): best for Ryobi 40V

Ryobi lists an adjustable 15 to 17-inch swath, a bump-feed REEL EASY+ head that takes 0.105-inch heavy-duty line, a carbon fiber shaft, and a variable-speed trigger with a two-speed switch, per Ryobi’s product page. It quotes up to 67 minutes with a 40V 6Ah battery and says the Whisper Series design is 72% quieter than gas.

Why it’s a good choice:

• The widest swath here, and the thickest line for tough weeds.
• Narrow the swath to stretch runtime, widen it for more cutting.
• Strong Ryobi 40V lineup to share batteries.

What to watch: Ryobi doesn’t list the weight, and the runtime figure needs a big 6Ah battery. It’s a bump-feed head, so you still tap it on the ground.

3. Milwaukee M18 FUEL 16″ String Trimmer (3046-20): best for Milwaukee M18

Milwaukee lists an adjustable 14 to 16-inch swath, 0.080 or 0.095-inch line, a 1.76 HP brushless motor and three speed modes (up to 4,600, 5,400 and 6,200 RPM), per Milwaukee’s product page. The Easy Load head holds up to 25 feet of line and loads in under 30 seconds, and the bail handle adjusts.

Why it’s a good choice:

• Three speed modes let you save battery on light grass.
• Runs on the M18 batteries many people already own for drills.
• Fast line loading without a spool to wind.

What to watch: it’s a dedicated trimmer and doesn’t take Milwaukee’s QUIK-LOK attachments. Milwaukee optimizes it for its large FORGE batteries, which are expensive, and the page doesn’t list weight.

4. Ryobi 40V HP Brushless 16″ Carbon Fiber (RY40HPST01B): best attachment-capable pick

Ryobi lists a 14 to 16-inch swath set by a tool-free sliding guard, 0.095-inch line, a variable-speed trigger with a two-speed switch and a carbon fiber shaft, per Ryobi’s product page. It works with RYOBI EXPAND-IT and other universal attachments, quotes more than 45 minutes with a 4Ah battery and carries a 5-year tool warranty.

Why it’s a good choice:

• Swap the trimmer head for an edger, pole saw or cultivator attachment.
• Ryobi says it out-powers a 27cc gas trimmer.
• REEL EASY+ head reloads in under a minute.

What to watch: battery and charger are sold separately, and the page doesn’t list weight or price. Some earlier Ryobi 40V attachment-capable trimmers are now discontinued, so check the exact model number.

5. EGO 16″ POWERLOAD Carbon Fiber (ST1610T): simpler EGO option

This is EGO’s POWERLOAD trimmer without LINE IQ. EGO lists a 16-inch swath, 0.095-inch twisted line, bump feed, a telescopic carbon fiber shaft and IPX4 weather resistance, per EGO’s product page. The ST1611T kit includes a 2.5Ah battery and quotes up to 30 minutes.

Why it’s a good choice:

• Keeps POWERLOAD, the feature most EGO owners like best.
• Same lifetime shaft warranty with registration.

What to watch: the small kit battery only runs about 30 minutes. EGO showed it as “Coming Soon” with no price, so check stock.

How to choose a cordless string trimmer

Swath

Swath is the circle the line cuts. 13 to 14 inches is fine for small yards. 15 to 17 inches clears more per pass but uses more battery. Ryobi’s adjustable guard is a sensible middle path.

Line diameter

• 0.065 to 0.080 inch: light grass and tidy edges.
• 0.080 to 0.095 inch: most suburban lawns, with some weeds.
• 0.105 inch: thick weeds and overgrown fence lines.

Thicker line lasts longer but needs more power. Use the size the maker lists, because the head and motor are tuned for it.

How the line feeds

This is the daily-use difference.

• Bump feed: tap the head on the ground to release more line. Cheap and reliable, but you’ll bump a lot in heavy work.
• Auto feed (EGO LINE IQ): the trimmer feeds line on its own.
• Loading: EGO’s POWERLOAD winds line for you; Milwaukee’s Easy Load and Ryobi’s REEL EASY+ let you feed line through without opening the spool.

If you’ve ever stood in the driveway rewinding a tangled spool, the loading system matters more than a few extra minutes of runtime.

Shaft and handle

All five here use straight shafts, which reach under shrubs and decks better than curved ones. Carbon fiber cuts weight at the front of the tool. A telescopic shaft helps tall and short users share one trimmer.

Attachment capable or dedicated

Attachment-capable trimmers (like the Ryobi RY40HPST01B) let one power head run an edger, pole saw or hedge attachment. Dedicated trimmers are usually better balanced. If you only trim, go dedicated.

Runtime and battery

Runtime claims are usually at the low speed with a large battery. For a quarter-acre lot, 30 to 45 real minutes is plenty for trimming. On larger yards, a spare battery is cheaper than a bigger trimmer.

Stay in one battery family

Your trimmer, blower and mower should share batteries. See my comparison of battery yard tool systems and the EGO vs Ryobi vs Greenworks mower guide.

How to trim neatly

1. Mow first, then trim. You’ll see exactly what the mower missed. My guide on how to mow a lawn covers mowing height.
2. Tilt the head slightly so the line tips do the cutting, not the whole length.
3. Walk with the line spinning away from hard edges so debris flies onto the lawn, not at you or the house.
4. Don’t scalp. Keep the head level and match the height of the mowed lawn.
5. Keep line off tree bark. String trimmers damage young trees quickly. A mulch ring around the trunk removes the need to trim there.
6. Use the low speed for light grass and save high for weeds.

Edging with a trimmer

Rotate the trimmer so the head is vertical and walk along the driveway or path. The line cuts a clean edge where grass meets concrete. It takes practice, and a dedicated edger is faster on long runs, but most homeowners get a good result after a few weekends.

Basic care

• Clean the head after each use, especially with auto-feed systems where grass can pack in.
• Store line in a sealed bag. Old, dry line breaks more often.
• Store batteries indoors in winter, at a partial charge, away from heat. Follow the maker’s storage notes.
• Check the guard blade (the small cutter that trims the line to length). A dull one makes line uneven.

When to trim through the season

Trim every time you mow during active growth. For cool-season grass in the North, that’s heaviest in spring and fall. For warm-season grass in the South, it’s heaviest in summer. My lawn care calendar lays out the season month by month.

My pick

If you want the least fuss, the EGO ST1623T is the trimmer to buy: no bumping, button-wound line and long runtime. Ryobi 40V owners get a wider swath and heavier line with the RY402011BTL. If your batteries are red, the Milwaukee 3046-20 is a strong, fast-loading trimmer, as long as you’re fine without attachments.