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Finding a 40V trimmer that actually finishes your yard without dying halfway is the real challenge here. You want the power to slice through thick weeds, but you also need a machine that is light enough to swing for an hour and built to survive more than one season. This guide breaks down the top cordless picks by what matters most — cutting width, battery life, and real owner feedback.
I’m Mo Maruf — the founder and writer behind The Tools Trunk. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
From 13-inch edgers to 17-inch brush cutters, these are the cordless trimmers worth your money this season. We have evaluated the best 40v string trimmer models on the market, and this is the definitive list.
Our Picks at a Glance
How To Choose The Best 40V String Trimmer
If your grass gets thick and you are tired of gas fumes and pull cords, a 40V trimmer gives you the power you need without the hassle. The spec sheet can still feel like a maze, so here is what actually matters for your yard, in plain terms.
Cutting Width: Bigger Is Not Always Better
The cutting width (usually 13 to 17 inches) is how wide a path the trimmer clears in one pass. A 17-inch head covers more ground faster, meaning fewer passes and less time. But a wider head can feel heavier and harder to maneuver around flower beds. If you have a small yard with lots of obstacles, a compact 13-inch model is easier to control. If you have open lawn, the wider swath saves you real time.
Battery System: The Real Cost Is Hidden Here
Some trimmers are “bare tools” — you pay less upfront but must already own compatible batteries and a charger. Others are complete kits that include everything. Before you buy, check whether the battery is shared across other tools you own (like a leaf blower or chainsaw). Buying into a good battery system saves you hundreds of dollars later, even if the trimmer itself costs more now.
Line Thickness and Feed Type
Thicker line — like.095 inches — cuts through tough weeds and brush without snapping as often. The feed type matters too: bump feed heads release new line when you tap the head on the ground, while automatic feed spools do it for you but can jam. For heavy-duty work, a thicker line with a reliable bump feed is usually the better bet.
Quick Comparison
| Model | Best For | Cutting Width | Weight | Battery Included | Amazon |
|---|---|---|---|---|---|
| Kobalt 40V Max 15-in★ Best Overall | Small yards, easy handling | 13 inches | — | No (Bare Tool) | Amazon |
| Greenworks 40V 12-InchBest Value | Budget-friendly trimming | 12 inches | 8.4 lbs | No (Bare Tool) | Amazon |
| 40V 14″ WugekuCompact Pick | Brush clearing, foldable storage | 14 inches | 6.8 lbs | Yes (2 x 4.0Ah) | Amazon |
| RB 17″ Cordless | Wide swath coverage | 17 inches | 6.6 lbs | Yes (2.0Ah) | Amazon |
| BLACK+DECKER LST136 | Suburban lawns, trimming + edging | 13 inches | 7.8 lbs | Yes (2.0Ah) | Amazon |
| DongCheng Brushless | Lightweight, shoulder strap comfort | 15 inches | 7.3 lbs | Yes (2 x 4.0Ah) | Amazon |
| RYOBI 40V Attachment Capable | Expandable tool system | 13 inches | 11 lbs | No (Bare Tool) | Amazon |
| SKIL PWR CORE 40 Combo | Trimmer + blower kit | 14 inches | — | Yes (2.0Ah) | Amazon |
| Worx WG186.9 | Gas-like power, attachment compatible | 15 inches | 8.8 lbs | No (Bare Tool) | Amazon |
| SKIL Multi-Head 16″ | Versatile multi-head system | 16 inches | 14.5 lbs | Yes (4.0Ah) | Amazon |
| Wild Badger 4-in-1 | Complete yard care kit | 15 inches | 26.5 lbs | Yes (2 x 4.0Ah) | Amazon |
In‑Depth Reviews
1. Kobalt 40-Volt Max 15-in Straight Cordless Bare Tool String Trimmer
Our pick — 4.5★ from 400+ verified ratings; the strongest balance of quality and price.
The crowd-pleasing trimmer that handles an entire yard on a single charge.
This trimmer cuts a 13-inch path (the width of the cutting swath) with a 6000 RPM motor (revolutions per minute, or how fast the line spins), so it powers through thick grass without bogging down. The straight shaft lets you reach under fences and around flower beds, and the lightweight build keeps your arms from tiring during longer sessions. Because it is a bare tool (no battery or charger included), you only pay for the trimmer itself — a smart buy if you already own Kobalt 40V batteries.
Buyers report: “No problem doing an entire yard on a single charge.” That is the recurring theme — for smaller properties, one battery is genuinely enough. Owners praise its easy assembly and reliable cutting through most weeds. The weight is the only mixed note — it starts light but can feel heavier during extended use, so a shoulder strap helps if you have a larger yard.
One honest caveat: because it’s a bare tool, you need to factor in the cost of batteries and a charger if you don’t already have them. As a brand-agnostic pick that delivers reliable trimming without gas or cords, this is the most balanced option here — which is why it holds the top spot with a strong crowd following.
What Wins Owners Over
- Battery life is the headline — full yard on one charge
- Lightweight with a straight shaft for better reach
- Easy to assemble from the start
- Dual-line bump feed head for quick line advancement
Before You Buy
- Bare tool — batteries and charger sold separately
- A little long for tight spaces
- Weight becomes noticeable during longer trimming sessions
Reach for this if: you want a proven, balanced trimmer for small-to-medium yards and already own — or plan to buy — Kobalt 40V batteries.
Look elsewhere if: you need a complete kit with batteries in the box today, or you have a large property that demands a wider cutting swath.
2. Greenworks 40V 12-Inch Cordless String Trimmer, BST4000
The budget-friendly bare tool with surprising power and a 60-minute rated runtime.
At 8.4 pounds, this is not the lightest trimmer here, but the variable-speed trigger gives you control to ease around plants and shrubs. The 12-inch cutting path uses.065-inch line with an auto-feed head, so you don’t have to stop and tap the head to get more line out. It’s compatible with GreenWorks G-MAX 40V batteries, which is a huge plus if you’re already in that ecosystem.
The power story is strong — owners mention it “battery lasts for 2-acre property,” which is remarkable for a 12-inch model. Quality is the most-praised aspect, with owners noting it powers through thick weeds and saplings without slowing down. However, durability is genuinely mixed: some units have broken after two months of use, so this is a value pick rather than a lifetime investment.
If you want a low-cost entry into the 40V world and already own GreenWorks batteries, this is the smart money move. It’s also a great spare tool to keep for quick touch-ups, even if your main trimmer is a heavier-duty model.
Standout trait: The variable-speed trigger is the defining feature — it lets you feather the power for delicate work around flower beds, then open it up for tough grass. That control, paired with the auto-feed head, makes it easier to use than most budget trimmers.
Fair warning: The mixed durability reports mean you should treat it gently and not push it into heavy brush clearing on a regular basis.
Best suited for: budget-conscious buyers who already own GreenWorks 40V batteries and want a reliable second tool or a first trimmer for a small yard.
Think twice if: you need a do-everything machine for a large, overgrown property — the 12-inch width and mixed durability make it less ideal for heavy abuse.
3. 40V 14″ String Trimmer,.095″ Dual Line, Fits Makita 18V LXT
The foldable trimmer that slips into your trunk and still clears heavy brush.
At 6.8 pounds, this is the lightest trimmer in our lineup — noticeably lighter than the 8.4-pound Greenworks — yet it packs a brushless motor that delivers serious torque. The 14-inch cutting width uses a thick.095-inch dual line, and it includes a 3T blade, a 40T alloy blade, and a string spool head for versatility. You get 40V output by connecting two included 20V 4.0Ah batteries in series.
Customers note: “batteries worked the whole 3 hrs” — impressive runtime that covers most full-yard jobs. The battery life and easy assembly are the top praised aspects, with owners loving that it cuts between tree stumps and removes everything in its path. The foldable shaft design is a genuine space-saver for garages and car trunks, using a quick-release hinge for tool-free assembly.
The trade-off is that the head has had durability complaints — some reviewers point out it breaking apart during heavy use. It’s a powerful, feature-rich package for the money, but treat the head gently and it will serve you well.
Why It Stands Out
- Foldable shaft — compact storage in garage or trunk
- Includes blades AND string head for versatility
- Lightest pick at 6.8 pounds
- Impressive 3-hour battery runtime reported
Keep In Mind
- Head durability is the recurring complaint
- Uses two 20V batteries — you manage two packs
- Some report missing strap nut in packaging
Grab this if: storage space is tight and you need a light, powerful trimmer that also handles brush with its included blades — it outperforms most electric trimmers in its class.
Pass if: you want maximum durability for heavy weekly abuse, or you prefer a single-battery system over managing two 20V packs.
4. RB 17″ 40V Cordless String Trimmer with 2Ah Battery & Charger
The widest cutting swath on this list — 17 inches — meaning fewer passes and faster finishing.
With a 17-inch cutting width and a heavy-duty.095-inch dual line, this trimmer covers more ground per pass than any other pick here — a full 4 inches wider than the Kobalt’s 13-inch swath. The bump feed “Tap & Go” head releases line simply by tapping the head on the ground, with no complicated auto-feed mechanism to jam. At 6.6 pounds, it’s also among the lightest options, making the wide head surprisingly easy to control.
Owners call it a “beast” that cuts through thick vegetation like butter while staying relatively quiet. Owners highlight its build quality and simple operation., and the 2-in-1 trimmer/edger conversion — rotating the head in seconds with no tools — adds real versatility. Battery life is mixed: some say it lasts longer than expected, while others note the 2.0Ah battery takes up to 4 hours to charge.
The two-speed design with low vibration is a comfort win, and the kit includes 4 rolls of trimmer line. Just be patient with the included charger — it’s the weakest link in an otherwise impressive package.
Standout spec: The 17-inch cutting width is the class leader here, and it’s backed by a 6.6-pound weight that makes it feel far lighter than its size suggests.
The catch: The charger is slow — up to 4 hours for a full charge — so plan your charging around your mowing schedule.
Choose this for: medium-to-large yards where the wide swath saves real time, and you want the convenience of a trimmer that converts to an edger in seconds.
skip it if: you can’t tolerate a slow charger, or you have a mostly small yard with tight corners where a wide head is harder to maneuver.
5. BLACK+DECKER 40V MAX 13 in String Trimmer Edger, LST136
The battery-powered workhorse with a PowerCommand dial and speeds up to 8500 RPM.
This is the complete kit — trimmer, a 2.0Ah battery, fast charger, and spool all in the box. The PowerCommand dial lets you choose between maximum power for thick weeds or maximum runtime for longer trimming sessions, and the auto-feed spool (AFS) supplies line automatically with no bumping required. It converts from trimmer to edger in seconds, making it a true 2-in-1 for lawn care.
With a 13-inch cutting width and an adjustable telescoping pole, it’s built for comfort during extended use. Owners praise its build quality and battery life, making it a crowd favorite. Rivals with more power exist, but few match this one’s balance of price, ease of use, and proven reliability for suburban lawns. It operates at speeds up to 8500 RPM, which is why it handles dense grass so well.
One honest note: the single-string design cuts a bit slower than dual-line models, and replacement batteries are pricey. But for typical suburban yards under 45 minutes of work, this is the proven, dependable choice that keeps coming back season after season.
What Makes It Reliable
- PowerCommand dial — max power or max runtime
- Auto-feed spool — no bumping required
- Converts to edger in seconds
- Fast charger restores battery in 2 hours or less
- Adjustable telescoping pole for comfort
Consider This
- Single string cuts slower than dual-line models
- Replacement batteries are a significant cost
- Occasional battery failures reported after limited cycles
Best for: suburban homeowners with standard-size lawns who want a complete, easy-to-use kit that also edges — the most proven pick on this list for daily reliability.
Not for: half-acre-plus properties or heavy brush clearing where a wider swath and thicker line would save significant time.
6. DongCheng Brushless String Trimmer, 6000RPM, 40V with Shoulder Strap
The well-balanced trimmer that pairs a shoulder strap with a brushless motor for fatigue-free sessions.
Running at up to 6000 RPM with a 15-inch cutting width and.095-inch line, this trimmer delivers powerful, precise cuts. The kit includes two 20V 4.0Ah batteries (working together as 40V) and a fast charger that restores them in about 1 hour. The ergonomic handle and weight distribution system, plus the included shoulder strap, are designed to reduce arm strain — and at 7.3 pounds, it’s genuinely manageable.
The runtime is rated at 45 minutes on low speed, which one owner confirmed handles all trimming on a small tree farm. Owners describe it as “Makita quality, Ryobi price” — a serious piece of equipment that’s very powerful with 3 power settings. The weight is the honest trade-off: it’s heavier than some, and the grip can feel awkward for taller users.
The 3-year warranty on garden tools covers defects, so you are protected if something fails. The dual-battery system (two batteries that swap between tools) works within the DongCheng 20V platform, letting you share batteries across your gear. This is a solid mid-range option that delivers more value than its price suggests.
Impressive value: Two 4.0Ah batteries and a 1-hour charger included — a rare find at this tier, making it a serious contender for value.
Honest note: The batteries are incompatible with other mainstream platforms, so you’re committing to the DongCheng ecosystem.
Pick this if: you want a complete kit with two batteries, a fast charger, and a comfortable shoulder strap for longer trimming sessions.
Look past it if: you already own batteries from another brand, or you’re on the shorter side — the grip and length suit taller users better.
7. RYOBI 40V Attachment Capable 15″ String Trimmer Bare Tool
The attachment-capable system that grows with your yard — up to 71 minutes of runtime.
This 40V trimmer is Expand-It attachment capable, meaning you can swap in edgers, blowers, and other heads from the RYOBI 40V line. It delivers more power than a 21cc gas trimmer, making it a true gas replacement. Using a 40V 4Ah battery, you get up to 71 minutes of runtime — one of the longest on this list.
Owners who upgraded from the 18V version note this is “a lot more powerful,” and the bump head string feeder works great. Owners praise its build quality and lightweight, gas-free operation. Loading new line is easy, and the 13-inch cutting width is standard for the category.
The honest downsides: the vibration on the trigger hand is intense for some, and there are rare fire-safety concerns reported — a small number of owners mention the tool getting very hot during use. If you’re already in the RYOBI 40V ecosystem, this is the obvious upgrade path; if not, weigh the ecosystem commitment carefully.
Why It’s Popular
- Expand-It attachment capable — build a full tool system
- 71-minute runtime with a 4Ah battery
- More power than a 21cc gas trimmer
- Easy line loading
Watch Out For
- Intense vibration on the trigger hand for some users
- Bare tool — battery and charger not included
- Rare reports of overheating during use
Go with this if: you’re building or already own a RYOBI 40V tool system, and you want one trimmer that handles multiple yard tasks through attachments.
Reconsider if: vibration bothers you, or you’re not invested in the RYOBI battery platform — the bare-tool format only pays off if you have batteries already.
8. SKIL PWR CORE 40 Brushless 14-Inch String Trimmer and 460CFM Blower Combo Kit
Two yard tools in one box — a 14-inch trimmer plus a blower that hits 460 CFM.
This combo kit gives you both a string trimmer and a leaf blower on the same 40V system, sharing one 2.0Ah battery and a 60W charger. The 14-inch cutting swath with dual-line bump feed is efficient, and the Twist Load head lets you insert line and twist to load — no fumbling. The blower delivers up to 460 CFM with a 120 MPH air speed, plus variable speed control with turbo boost.
Owners are impressed with the value, calling the pair “great machines for the money” and noting the battery lasts long enough to get the whole yard done. The quick-release tube on the blower makes for compact storage. The IPX4 weather resistance means it holds up in light rain, which is a real bonus for a cordless tool.
The catch: with just one 2.0Ah battery shared between two tools, you may want a second battery if your yard is large. But for typical weekly upkeep — trimming then blowing — this bundle covers both jobs out of one box.
Bang for buck: This is the most complete starter package — trimmer, blower, battery, and charger — for anyone who needs both tools anyway.
Keep in mind: One shared 2.0Ah battery means you’ll be swapping between tasks, not running both simultaneously.
Buy this if: you need both a trimmer and a leaf blower and want them on one battery system out of a single box.
Skip if: you already own a blower, or your yard is so large that a single 2.0Ah battery won’t stretch across both jobs.
9. Worx Cordless String Trimmer, 40V 15″ Electric Weed Wacker, WG186.9
The gas-replacement trimmer with a brushless motor and DriveShare attachment compatibility.
Worx designed this Nitro trimmer to mimic gas power, and the 15-inch dual-exit cutting head (two line exits for a wider cut) with easy-load design (no tools needed to reload line) supports that claim. The brushless motor (no brushes to wear out) runs more efficiently, and the variable speed control with ECO-mode (a power-saving setting) stretches battery runtime. The DriveShare split-shaft design (the shaft splits to accept attachments) works with most other brands’ tools, making this the most versatile trimmer in this list.
At 8.8 pounds, it’s on the heavier side, and owners note the included strap is not enough — a full-body harness is better for extended sessions. The power is genuinely impressive; one owner calls it “an absolute beast” that cut through thick overgrown garden beds while staying quiet and balanced. Battery life is the main mixed note — 4Ah batteries drain fast under heavy load, so budget for larger 6Ah packs if you buy in.
The universal compatibility and gas-like cutting power make this a top pick for anyone who wants electric convenience without sacrificing performance. Just be ready to add a better harness and larger batteries.
What Makes It Strong
- Gas-like power with a 15-inch cutting width
- DriveShare attachment capable — fits most brands
- Brushless motor for efficiency and longevity
- ECO-mode for extended runtime
What Holds It Back
- Heavy — needs a full-body harness, not the included strap
- Battery life is mixed; 4Ah packs drain fast under load
- String loading can be difficult
Choose this for: serious trimming and brush clearing where you want gas-level power on a versatile, attachment-capable platform.
Think again if: you want a lightweight trimmer, or you’re not prepared to invest in larger batteries and a proper harness to get the best experience.
10. SKIL PWR CORE 40 Brushless Multi-Head System, 16-Inch String Trimmer Kit
The 16-inch multi-head system that runs 25% longer thanks to its cooling-wrapped cells.
This is the most powerful trimmer kit here — a 16-inch cutting swath that chews through tall grass and thick weeds. The digital brushless motor provides efficient, high-performance power, and the included 4.0Ah battery uses PWR CORE technology that wraps each cell with cooling material for 25% longer runtime and 2X battery life. The Twist Load head makes line changes simple — insert and twist.
With 20 owners praising its effectiveness against stubborn weeds, this is a top performer that also runs about 45 minutes on a charge. The dual-line bump feed releases line by tapping the head on a flat surface, and the two-speed selector lets you choose between maximizing power or runtime. The adjustable auxiliary grip adds control during extended sessions.
The weight is the honest trade-off — at 14.5 pounds with the big 4.0Ah battery, it’s the heaviest trimmer head here. But that weight translates to serious cutting power. For the multi-head capability and the longest cutting width at a strong rating, this is a premium pick that justifies its position.
Premium performance: The 16-inch swath is the widest of our top picks, and the PWR CORE cooling technology genuinely extends runtime versus standard packs.
Honest trade-off: That power and battery come with weight — 14.5 pounds is substantial, so plan for a strap if you’re doing long sessions.
Invest in this if: you want the widest cutting swath and longest battery life in one premium multi-head system, and you’re comfortable with the weight.
Look elsewhere if: weight is your primary concern, or you don’t need the multi-head attachment capability.
11. Wild Badger Power Upgraded 40V Cordless String Trimmer & Edger, 4-in-1 Multi-Tool Kit
The full-yard kit — trimmer, brush cutter, hedge trimmer, and pole saw in one box.
This is the complete yard-care solution: a 15-inch string trimmer/edger, an 8-inch pole saw, a 16-inch hedge trimmer, and a 0.095-inch line/10-inch brush cutter. The upgraded 40V (2x20V) high-performance motor delivers consistent power for thick grass, weeds, branches, and overgrowth. The quick-connect design lets you switch attachments in seconds with no special tools.
Owners call it exceptional for DIY landscaping — it “cuts brush and branches up to 1.5 inches” thick, and the batteries last 35-45 minutes per charge, which is sufficient for most sessions. The value is the top praised aspect, with two batteries included so you can keep working while one charges. The low-vibration internal structure improves comfort during long sessions.
The honest downsides: at 26.5 pounds for the full kit, it’s heavy, though the included strap helps. The assembly instructions are unclear, particularly for the handle and string refill. And the battery life is mixed — some shoppers say closer to 20 minutes under heavy load. This is a value-packed multi-tool for DIYers who want one system for the whole yard.
Why It’s A Deal
- 4 tools in one box — trimmer, brush cutter, hedge trimmer, pole saw
- Two 4.0Ah batteries included
- Quick-connect attachment switching
- Cuts brush and branches up to 1.5 inches thick
Be Aware
- Heavy kit at 26.5 pounds — strap essential
- Battery life mixed; some report ~20 minutes under load
- Assembly instructions are unclear
Buy this for: DIY landscapers who want one tool system that trims, cuts brush, prunes hedges, and handles pole saw work without buying four separate tools.
Pass if: you only need a simple trimmer, or you want a lighter, more focused tool rather than a heavy multi-head kit.
Understanding the Specs
Cutting Width and Line Thickness
Cutting width — measured in inches from 12 to 17 — is how wide a swath the trimmer clears per pass. Wider is faster on open lawn but harder in tight spaces. Line thickness (.065 vs.095 inches) matters more for toughness: thicker line cuts through weeds and brush without snapping. Dual-line heads cut faster than single-line designs but use more line.
Battery System and Bare Tools
Bare tools come without batteries — you supply your own from the brand’s platform. Kits include batteries and a charger. The 40V class typically uses either a single 40V pack or two 20V packs wired in series. Runtime claims (45 to 71 minutes) are measured at low speed on a fresh battery; real-world runtime varies with grass thickness and speed setting.
FAQ
Will a 40V trimmer replace my gas trimmer?
What does “bare tool” mean for a string trimmer?
Is a wider cutting width always better?
How long does a 40V trimmer battery actually last?
What is the difference between bump feed and auto-feed heads?
Can I use my existing 20V batteries in a 40V trimmer?
What line thickness should I use for thick weeds?
Is a brushless motor worth the extra cost?
How do I convert a trimmer into an edger?
Final Thoughts: The Verdict
If you want one dependable pick, the 40v string trimmer winner is the Kobalt 40V Max because it balances a 6000 RPM motor, a 13-inch cutting width, and proven battery life that handles an entire yard on one charge. If you want a complete kit with edging capability and a massive owner following, grab the BLACK+DECKER LST136. And for maximum power with a 16-inch swath and longest battery life, the SKIL Multi-Head System is the one to reach for.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of August 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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