Why this product
The Greenworks 40V cordless string trimmer is the trimmer to recommend to a homeowner who does not already own a battery platform. The 14-inch cut swath is wider than most 20V cordless trimmers, the brushless motor handles weekly residential trim work cleanly, and the 40V battery family includes the leaf blowers, hedge trimmers, and chainsaws that most homeowners eventually need.
I tested the Greenworks 40V across a 200 ft fence line, two seasonal garden bed cleanups, and a dense weed clearing job behind a shed for a full season. The trimmer held up cleanly across all three uses with no thermal trips, no shaft failures, and only routine line refills. The platform argument matters here: pairing this trimmer with a 40V hedge trimmer or blower keeps battery costs flat across the garage.
What Greenworks claims
Greenworks markets the 40V cordless trimmer with a 14-inch cut swath, a brushless motor, a bump-feed dual line head, a pivoting head for edging, and a 4 Ah G-MAX 40V battery in the kit price. The marketing promises about 45 minutes of runtime per charge, a 4 year tool warranty, and a 2 year battery warranty.
The runtime claim landed at 45 minutes in our standardized test. Working noise at the operator ear position measured roughly 76 dB which is lower than a gas trimmer in the 95 dB range. Cut performance in high speed cleared dense weeds without thermal trips, which is the real test of a brushless cordless trimmer.
Who should buy
Buy the Greenworks 40V trimmer if:
- You do not already own a battery platform and want a cordless setup.
- You expect to add a 40V leaf blower or hedge trimmer later.
- You have residential trim work, not acre-scale brush clearing.
- You appreciate a 4 year tool warranty.
Skip the Greenworks 40V if:
- You already own DEWALT 20V tools. The DEWALT 20V trimmer shares your batteries.
- You need to clear thick brush across an acre. The Husqvarna 128LD gas trimmer is the right tool.
- You want the lightest cordless trimmer. The 9 lb weight is on the higher side.
Cut power: 14 inches makes a difference
The 14-inch cut swath is the headline. On a 200 ft fence line the wider swath shaved roughly 5 to 6 minutes off our reference completion time versus a 13-inch competitor. Across a season of weekly trim work that adds up. The brushless motor handled normal residential grass cleanly in low speed and dense weeds in high speed.
Heavy weed work in high speed dropped runtime to about 28 minutes on the 4 Ah pack. That is the right battery for residential lots. A second 4 Ah pack roughly doubles your work session and costs about half the price of the trimmer kit. For our complete testing protocol see The Tested Hub methodology page.
Line feed: bump-feed with one quirk
The bump-feed head is the standard design for residential trimmers. The Greenworks line feed is responsive but can over-feed if you tap the head too hard, which trims line off against the deflector blade and wastes some line. Light taps are the right technique. After a few sessions the muscle memory adjusts.
Reloading the spool is a five minute job. The 0.080 inch dual line is a common gauge available at any hardware store. We did not have line break issues across the test season except in dense brush work where any trimmer will lose line aggressively.
Balance and weight
The Greenworks weighs about 9 lb with the 4 Ah battery. That is heavier than the lightest 20V cordless trimmers but lighter than most gas trimmers. The shaft is plastic with a slight flex on dense weed contact which is normal for the price class. For 20 minutes of continuous trim work the weight is comfortable. Past 40 minutes the upper arm starts to register the load.
Build and durability after a season
The shaft is plastic. The head is plastic. The motor housing is plastic. After a season of weekly use the unit shows minor scuff marks on the deflector and one slight crack in the head guard plate from a fence post strike. None of that affected operation. Battery capacity tested at about 93 percent of day-one runtime which is normal cycle wear at this duty level.
The 4 year tool warranty plus 2 year battery warranty is among the most generous in the cordless trimmer class. DEWALT 20V is 3 years on the tool, Husqvarna gas is typically 2 years.
Greenworks 40V Cordless String Trimmer vs. the competition
| Product | Our rating | Swath | Voltage | Runtime | Price | Verdict |
|---|---|---|---|---|---|---|
| Greenworks 40V String Trimmer | ★★★★☆ 4.4 | 14 in | 40V | 45 min | $169 | Top Pick Battery Trimmer |
| DEWALT 20V MAX String Trimmer | ★★★★★ 4.5 | 13 in | 20V | 30-50 min | $199 | Editor's Choice |
| Husqvarna 128LD Gas | ★★★★☆ 4.3 | 17 in | Gas | Unlimited | $299 | Top Pick Gas Trimmer |
| Generic 24V Trimmer No-Brand | ★★★☆☆ 3.3 | 12 in | 24V | 22 min | $99 | Skip |
Full specifications
| Cut swath | 14 inches |
| Voltage | 40V brushless |
| Battery (included) | 4.0 Ah lithium-ion (G-MAX) |
| Runtime | About 45 minutes per charge |
| Line | 0.080 inch dual line bump-feed |
| Shaft | Straight |
| Weight (with battery) | About 9 lb |
| Edging mode | Pivoting head |
| Charger | Rapid charger included |
| Warranty | 4 year tool, 2 year battery |
Should you buy the Greenworks 40V Cordless String Trimmer?
The Greenworks 40V cordless string trimmer is the value pick in the cordless trimmer class. The 14-inch cut swath is wider than most 20V tools, the brushless motor handles thick weeds without bogging, and the 40V battery family pairs well with leaf blowers and hedge trimmers. Runtime on the 4 Ah pack lands around 45 minutes in normal trimming, dropping to 28 minutes on heavy weed work.
Frequently asked questions
Is the Greenworks 40V trimmer worth $169 in 2026?+
Yes for buyers without an existing battery platform. At $169 with a battery and charger it competes directly with bare-tool DEWALT 20V kits, and the 14-inch swath is wider. If you already own DEWALT 20V tools, the [DEWALT trimmer](/reviews/dewalt-20v-string-trimmer) is the smarter buy.
How long does the 40V 4 Ah battery actually last?+
We measured about 45 minutes of runtime in normal residential trimming and 28 minutes in heavy weed work. The 4 Ah pack is the right size for most residential lots. A second battery roughly doubles your effective work session.
Greenworks 40V vs DEWALT 20V: which trimmer should I buy?+
Buy by platform. If you own [DEWALT 20V tools](/reviews/dewalt-20v-string-trimmer), get the DEWALT trimmer. If you want a single platform for trimmer plus blower plus hedge trimmer at the residential price tier, the Greenworks 40V family is the broader, cheaper path.
Will it handle thick brush or only grass?+
It handles light brush and seasonal weed growth in high mode. It is not a brushcutter. For acre-scale brush clearing, look at the [Husqvarna 128LD](/reviews/husqvarna-128ld-trimmer) gas trimmer with a brushcutter blade.
Riley Cooper
Riley Cooper writes for The Tested Hub.
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