We may earn revenue from the products available on this page and participate in affiliate programs. Learn More ›
The professional-grade Bosch GRT18V-40 brushless string trimmer came out in early 2026, and I got a chance to try one soon thereafter. Recent generations of battery-powered landscaping tools have begun to match or surpass the raw power of their gas-fueled counterparts. Now, more design focus has shifted toward improving the overall operator experience. I wanted to find out whether or not the feature upgrades really moved the needle.
The GRT18V-40 is a powerful brushless string trimmer designed for heavy-duty yard work. It delivers working power equivalent to a 600-watt corded electric motor, at speeds up to 5,300 RPM. The included trimmer head is compatible with .080 and .095 trimmer line sizes and cuts a 16-inch swath. With the included battery installed, it weighs in at about 15 pounds.
Key Takeaways
- Powerful performance. The Bosch GRT18V-40 delivers cutting power equivalent to a 600-watt motor, outperforming a 25cc gas trimmer in heavy weeds.
- Extended battery life. New tabless batteries offer up to 90 minutes of light trimming per charge, enhancing runtime and output.
- Innovative features. Includes an anti-tangle system, variable throttle, and dual-function grips for improved user experience.
- Weight balance issue. At 15 pounds, the trimmer is front-heavy, lacking a shoulder strap for better weight distribution.
Bottom line: The Bosch GRT18V-40 is a powerful, battery-operated string trimmer ideal for midsize to large properties, offering strong performance and innovative features despite some balance concerns.
What We Like
- Lots of cutting power
- Ample runtime for average-size yards
- Highly responsive throttle trigger
- Good reach for trimming around shrubs
What We Don’t Like
- Head-mounted motor throws off the weight balance
- Shoulder strap not included or available from Bosch
Product Specs
- Battery type: 18V 4Ah lithium-ion battery
- Runtime: 23 minutes (on full power)
- Weight: 10 pounds
Performance and Runtime
The kit I received came with the new Bosch Expert 18-volt 8-amp-hour tabless battery and charger. These new tabless batteries work with the entire AMPShare ecosystem, offering more power and runtime than earlier battery technologies. For this release, Bosch rolled out an exclusive anti-tangle system to improve cutting performance and reduce downtime when working through heavy weeds. The trimmer also features an upgraded variable throttle and adjustable dual-function (trimming/edging) hand grips.
I tested the GRT18V-40 for 3 months in my own yard. I used it for the normal trimming that accompanies weekly mowing, edging along the driveway and curb, and for cutting back high, weedy areas at the back of the property. My overall impression was that it was great. It actually offered more cutting power in the tall weeds than my 25cc 2-cycle trimmer. The shortest runtime I clocked was 23 minutes per charge while running it at full power nonstop in heavy weeds. I got over 90 minutes of average/light trimming time per charge.
Limitations and Final Thoughts
My only negative impression was of the weight balance. At roughly 15 pounds with the battery equipped, it weighs about the same as my gas trimmer, but the motor mounted above the trimmer head creates a front-heavy situation. While that’s fine for heavy growth, it makes using it more tiring than necessary for average trimming conditions. You can correct the balance somewhat by moving the loop handle down the shaft, but not perfectly. Also, the kit did not include a shoulder strap to help transfer the weight, and it doesn’t look like Bosch offers one.
The Bosch GRT18V-40 brushless string trimmer has a lot to offer folks who own properties that are midsize or larger. Most notably, it features strong, pro-quality trimming power with ample runtime per charge. I thought the new throttle trigger offered exceptional control through the full speed range. The batteries were noticeably better in terms of runtime and output than prior Bosch batteries I’ve used. If you’re looking for a new battery string trimmer, this one offers strong performance at a fair price.
Where to Buy
Photo: Mark Wolfe for BobVila.com
