Best 40V Cordless String Trimmers (2026)

The 16 inch Greenworks has the widest cutting path in this guide and uses thick 0.095 inch dual line, much heavier than the 0.065 inch line on the smaller models. Thick line cuts tougher weeds and resists snapping, while the extra path means fewer passes along a long fence. A brushless motor gives more torque and runtime from the included 4.0Ah battery.

It is also attachment capable, meaning the powerhead accepts an edger, hedge trimmer, pole saw, cultivator and blower, so one motor serves several jobs. A two-speed mode with a variable trigger lets you save battery on light work.

The tradeoff is size, since a wider head is heavier and bulkier than a 13 inch model. Replace line as needed, clean the guard and store the battery inside. It suits larger yards.

The RYOBI lets you set the cutting width between 13 and 15 inches, trading runtime for reach: narrow for longer battery life, wide for faster passes. It accepts RYOBI Expand-It attachments and universal gas attachments, which means you can reuse tools from a gas system. A bump-feed head advances line when you tap it on the ground.

Compared with the Greenworks 16 inch, it has a narrower maximum path and does not state a brushless motor, so it is aimed at general yard work. It includes a 4.0Ah battery and a 90-minute charger, a quick charge compared with many.

Bump feed is simple and reliable but needs a tap. Replace line, clean grass from the head and store the battery indoors. It suits owners already in the RYOBI ecosystem.

The WORX WG183 runs on two 20V 2.0Ah batteries that together make up its 40V system, a different approach from the single 40V pack on the others. Because the batteries are shared across the maker's 20V and 40V tools, you can use them in smaller tools too. A dual-exit cutting head feeds two lines for more efficient cutting, and an auto feed spool advances line without bumping.

It is a light, simple design with an adjustable auxiliary handle, aimed at small yards. Its 13 inch path and thinner line mean it will not handle thick weeds as well as the Greenworks 16 inch.

Each pack is only 2.0Ah, so a long job may need both swapped in, but the pair ships with a dual charger. Clean the head and store the batteries indoors. It suits small yards.

The Litheli is a 2-in-1: swivel the head 90 degrees and it becomes a wheeled edger, which keeps a steady line along a walk. Variable speed up to 8500 rpm and an automatic line feed give control, and a flower guard keeps line a set distance from plants.

It is the heaviest in the guide at 9.9 pounds bare, and the 0.063 inch line is the thinnest, so it is a light-duty cutter. A telescopic, foldable shaft makes storage easy.

The included 2.0Ah battery and charger make it a complete kit, though a small pack. Replace line and clear the wheel. It suits owners who edge along walks.

The LST136B is the bare-tool version of the BLACK+DECKER trimmer edger, so battery and charger are sold separately. Its PowerCommand dial lets you pick maximum power for thick growth or maximum runtime for long areas, a useful control the Greenworks and RYOBI do not list. The PowerDrive transmission sends more motor power to the string.

It converts to an edger in moments and uses an automatic feed spool. Because it is tool only, the real cost depends on the 40V MAX battery you choose; buy it only if you already own one.

A three-year limited warranty is solid. Replace line, clean the guard and store the battery inside. It suits existing BLACK+DECKER owners.

The BST4000 is the simplest trimmer here: a 12 inch path, 0.065 inch auto-feed line and a variable speed trigger for working around plants. It is sold tool only, compatible with Greenworks G-MAX 40V batteries, so you need existing packs.

Its 12 inch path is the narrowest in this guide, and it does not list a brushless motor or attachment capability, unlike the Greenworks 16 inch. That makes it the light-duty option for owners with existing batteries.

Its operating range is 6.8 to 104F, a useful figure for cold-weather use. Clear the guard and store batteries inside. It suits owners with Greenworks batteries and small yards.