The Greenworks 40V 12-Inch Cordless String Trimmer is a lightweight battery-powered trimmer designed for residential lawn trimming, border edging, and moderate weed clearing.
It runs on a 2.0Ah 40V battery that recharges in 60 minutes and features an auto-feed head and variable speed trigger. The 12-inch cutting path suits small to medium yards well, and the unit is not intended for commercial or daily heavy-duty use.
Specifications
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Voltage: 40V
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Cutting Path: 12 inches
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String Diameter: 0.065 inch, dual-feed auto-advance head
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Speed Control: Variable speed trigger
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Battery Included: 2.0Ah 40V
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Charge Time: Approximately 60 minutes
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Start: Push-button
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Operating Temperature: 6.8°F to 104°F (trimmer); 39°F to 113°F (charger)
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Frame: Lightweight, ergonomic
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Edging Capability: Yes, via rotating head and flip-forward guide bar
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Emissions: None
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Replacement Spools: Available on Amazon
When the Greenworks 40V 12-Inch Trimmer Fits Your Yard and When It Does Not
If you maintain a small to medium residential yard and want a trimmer that starts instantly, runs quietly, and does not require gas or pull-cord startup, this unit covers standard border trimming, fence line work, and moderate weed clearing on a single charge.
The variable speed trigger lets you slow down around shrubs, garden beds, or tree trunks where full throttle would cause damage. The trimmer also converts to an edger by flipping the guide bar forward and rotating your grip, which gives you two-tool functionality without a second piece of equipment.
The 2.0Ah battery is sized for residential sessions rather than extended commercial runs. If your property is larger than a quarter acre with heavy, dense weed growth across the full area, a higher-capacity battery or a more powerful trimmer platform will serve you better.
What to Expect from the Greenworks 40V 12-Inch Cordless String Trimmer in Real Use
Assembly is straightforward for most users, with the handle clamp being the one step that can require a bit more effort to seat correctly. The trimmer starts with a push of a button every time, with no warm-up or priming required.
Battery life on the 2.0Ah pack covers approximately 30 to 45 minutes of active trimming, depending on conditions. One verified purchaser trimmed roughly a quarter acre of heavy grass and thick-stalk weeds across one and a half charges, running at full throttle for the denser sections. Another used a single charge for up to 45 minutes on standard residential trimming.
The auto-feed head advances line automatically in most conditions. Verified purchasers note that spool quality matters significantly. Pre-loaded replacement spools from third-party sellers have received criticism for line wound too tightly, which causes feeding issues.
Several verified purchasers report better results winding their own line onto the spool using quality aftermarket string, which also reduces the frequency of line advancement needed per session.
The trimmer handles thick-stalk weeds and overgrown areas with consistent power at full throttle. One verified purchaser used it to clear a heavily overgrown area that a lawn care professional had declined to touch, noting it powered through without issue.
Real-world performance notes sourced in part from verified Amazon customer purchases.
Frequently Asked Questions
Can this trimmer be used as an edger, and how does that work?
Yes. The trimmer converts to an edger by flipping a small metal guide bar forward on the head and rotating the way you hold the unit so the cutting line runs vertically rather than horizontally.
This lets you walk the trimmer along a sidewalk or driveway edge and cut a defined line without a separate edging tool. It is not a dedicated wheeled edger, but for standard sidewalk and driveway border work it performs the function adequately.
What replacement string and spool type does this trimmer use?
The trimmer uses 0.065-inch diameter string on a dual-feed auto-advance spool. Replacement spools are available on Amazon in single packs and multi-packs. Based on real-world use, winding your own line onto a compatible spool using quality aftermarket 0.065-inch string outperforms many pre-loaded replacement spools, which can be wound too tightly and cause feeding problems. Winding your own spool takes a few minutes and gives you control over line tension and string quality.
Does the 40V battery work with other Greenworks 40V tools?
Yes. The Greenworks 40V battery platform is shared across Greenworks' 40V tool lineup, including mowers, blowers, and other trimmers. If you own or plan to buy additional Greenworks 40V equipment, the batteries are interchangeable across the system. Purchasing additional 40V batteries separately extends your working time without waiting for the included 2.0Ah pack to recharge between sessions.
