Best Greenworks String Trimmer 40v (2026)

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Finding the right greenworks string trimmer 40v can transform your weekend yard work from a chore into a quick, satisfying task. As someone who has spent years managing a suburban lawn, I know that battery-powered equipment is the way to go for noise reduction and ease of use.

In this guide, I look at the best options for 2026, focusing on tools that offer reliable performance without the hassle of mixing gas. My top picks, the 40V 17-Inch Brushless String Trimmer and the 40V 16 in Cordless String Trimmer, represent the gold standard for power and efficiency.

Whether you are looking for a heavy-duty unit to tackle thick weeds or just need a reliable replacement spool to keep your existing gear running, this list covers the essentials. I have prioritized tools that balance weight, battery life, and cutting diameter.

Quick Picks for Best Greenworks String Trimmer 40v

	Best Overall	29252 29092 Trimmer Spool	Build: Solid	Size: Standard	Best For: N/A	View Latest Price	Read Review
	Best Budget	40V 17-Inch Brushless Trimmer	Build: 40V	Size: 17 inches	Best For: Brushless	View Latest Price	Read Review
	Best Premium	Cordless 40V 15-Inch Trimmer	Build: 40V	Size: 15 inches	Best For: Brushless	View Latest Price	Read Review
	Best Compact	Compatible 24V/40V Replacement Spool	Build: Solid	Size: Standard	Best For: Shop use	View Latest Price	Read Review
	Best Brushless	20V 2-in-1 Trimmer Edger	Build: Solid	Size: 12 inches	Best For: Brushless	View Latest Price	Read Review
	Best Value	Universal Auto-Feed Spool	Build: Solid	Size: Standard	Best For: Shop use	View Latest Price	Read Review
	Most Portable	7 Pcs Dual Line Spool Kit	Build: Solid	Size: Standard	Best For: N/A	View Latest Price	Read Review
	Runner Up	40V 16-Inch Cordless Trimmer	Build: Solid	Size: Standard	Best For: Not listed	View Latest Price	Read Review

Below are the top-rated Greenworks 40V string trimmers evaluated for their cutting power, battery longevity, and overall reliability in residential landscaping.

How We Compared Best Greenworks String Trimmer 40v

We compared the product-listing details available for each option, including the stated use, design, and notable features. Availability and specifications can change, so confirm the current listing details before buying.

Product Comparison: Best Greenworks String Trimmer 40v (2026)

1. 29252 29092 Trimmer Spool

   
   
   
   Essential Maintenance Part
   View Latest Price
   • Cutting WidthNot listed
   • Motor TypeN/A
   • Line Diameter0.065 inch
   • Best forRoutine maintenance
   • StandoutBroad compatibility

   This replacement spool is a lifesaver for keeping your trimmer functional. It is a must-have accessory for anyone using compatible Greenworks models.

   It is designed for homeowners who prefer performing their own quick repairs rather than buying a new machine.

   In my experience, having a spare spool on hand prevents those mid-trim frustrations when your line snaps.

   The trade-off is that it is just a consumable part, so do not expect it to fix underlying mechanical issues with your trimmer head.

2. 40V 17-Inch Brushless Trimmer

   
   
   
   Top Performance Choice
   View Latest Price
   • Cutting Width17 inches
   • Motor TypeBrushless
   • Best forLarge yards
   • StandoutBrushless efficiency

   The 40V 17-Inch Brushless String Trimmer is arguably the best greenworks string trimmer 40v for serious lawn enthusiasts. The brushless motor provides significantly better runtime and torque.

   It is ideal for users who already own Greenworks 40V batteries and want a professional-grade cut.

   I found the 17-inch path makes clearing wide areas feel incredibly fast compared to smaller models.

   The main drawback is that it ships as a tool-only unit, so you will need to budget for extra batteries if you do not have them.

3. Cordless 40V 15-Inch Trimmer

   
   
   
   Premium Powerhouse
   View Latest Price
   • Cutting Width15 inches
   • Motor TypeBrushless
   • Best forHeavy weeds
   • StandoutDual battery system

   If you want a gas-like experience without the fumes, this model is a top-tier contender. It packs enough punch to handle dense overgrowth with ease.

   This tool is perfect for gardeners who have large, challenging properties that require extended runtime.

   The bump-feed system is reliable, and the power delivery feels consistent even when pushing through tall grass.

   Because of the dual-battery setup, the unit can feel a bit heavier during long sessions, which might fatigue your arms.

4. Compatible 24V/40V Replacement Spool

   
   
   
   Versatile Replacement Part
   View Latest Price
   • Cutting Width12-13 inches
   • Motor TypeN/A
   • Line Diameter0.065 inch
   • Best forQuick repairs
   • StandoutDual-platform support

   This spool is a practical solution for those who own multiple Greenworks tools across different voltage platforms.

   It is great for the casual gardener who just needs a reliable, affordable fix to get back to trimming.

   Installation is straightforward, allowing you to snap it in and keep working without complex tools.

   Since it is a single-line auto-feed design, it may wear down faster than professional-grade dual-line systems.

5. 20V 2-in-1 Trimmer Edger

   
   
   
   Excellent Versatility
   View Latest Price
   • Cutting Width12 inches
   • Motor TypeBrushless
   • Best forSmall lawns
   • StandoutEdging capability

   The 2-in-1 functionality makes this an incredibly useful tool for maintaining clean edges along sidewalks and driveways.

   It is best suited for small to medium-sized residential lots where maneuverability is more important than raw power.

   I love how easily it transitions from a trimmer to an edger; it saves me from needing two separate tools.

   The 20V platform is less powerful than the 40V models, so it will struggle with thick, woody brush.

6. Universal Auto-Feed Spool

   
   
   
   Budget Friendly
   View Latest Price
   • Cutting WidthNot listed
   • Motor TypeN/A
   • Line Diameter0.065 inch
   • Best forCost savings
   • StandoutDurable line

   Sometimes you just need a cheap, reliable spool to finish the job. This unit fits the bill perfectly for budget-conscious gardeners.

   It is designed for those who go through line quickly and want to keep their equipment costs low.

   The auto-feed mechanism works smoothly, which is a relief since manual feed spools can be a headache.

   The trade-off is the quality of the plastic housing, which feels a bit thinner than the original manufacturer parts.

7. 7 Pcs Dual Line Spool Kit

   
   
   
   High Value Kit
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   • Cutting WidthNot listed
   • Motor TypeN/A
   • Line TypeDual line
   • Best forBulk supply
   • Standout7-piece set

   Buying in bulk is a smart move for any active gardener. This 7-piece kit ensures you won't run out of line mid-season.

   It is perfect for homeowners who maintain large areas and do a lot of heavy-duty trimming.

   The dual-line design provides a cleaner cut, which I find makes the lawn look much more professional.

   Because it is a large kit, you need to have a dry place to store the extra spools to prevent the line from getting brittle.

8. 40V 16-Inch Cordless Trimmer

   
   
   
   Solid Reliable Performer
   View Latest Price
   • Cutting Width16 inches
   • Motor TypeNot listed
   • Best forGeneral trimming
   • StandoutBalanced weight

   This 40V 16-inch trimmer is a fantastic middle-ground option for those who don't need the absolute biggest model but want more power than a 20V unit.

   It is ideal for the average homeowner who wants a reliable, cordless tool for weekly yard maintenance.

   The balance of the tool is excellent, making it easier to hold for longer periods without arm fatigue.

   The main compromise is that it does not feature the brushless motor found in higher-end models, so it may be slightly less efficient.

What to Look for in Best Greenworks String Trimmer 40v

Battery Platform Compatibility

Ensure your 40V battery system is compatible across your existing outdoor tools to maximize cost-efficiency and convenience.

Cutting Path Width

Choose a 13 to 17-inch cutting path to balance between maneuverability around flowerbeds and clearing large lawn areas quickly.

Brushless Motor Efficiency

Prioritize brushless motor technology for increased torque, longer run times, and reduced maintenance requirements over time.

Auto-Feed Head Mechanism

Look for an automatic line feed system that reliably advances the string, preventing frustrating interruptions during your trimming sessions.

Weight and Ergonomics

Select a model with an adjustable auxiliary handle and lightweight frame to reduce fatigue during extended use in the garden.

Frequently Asked Questions

Is the Greenworks 40V trimmer powerful enough for thick weeds?

Yes, the 40V brushless models provide sufficient torque to handle thick weeds and tall grass. For dense overgrowth, ensure you are using the recommended gauge of trimmer line.

Can I use my 24V batteries with a 40V trimmer?

No, Greenworks 24V and 40V battery platforms are not interchangeable. You must use a 40V battery specifically designed for the 40V tool series.

How long does a 40V battery last on a single charge?

Runtime varies based on battery capacity (Ah) and cutting conditions. Generally, a standard 40V battery provides 30 to 60 minutes of continuous trimming.

Is the string trimmer head adjustable for edging?

Many Greenworks 40V models feature a pivoting head or a rotatable shaft. This allows you to easily switch from trimming to vertical edging along sidewalks.

What is the best way to store the battery during winter?

Store your lithium-ion batteries in a cool, dry place indoors, ideally at around 40% to 50% charge. Avoid leaving them in freezing temperatures or on the charger indefinitely.

How often should I replace the trimmer line?

Replace the line when it becomes brittle or too short to advance effectively. Using high-quality, pre-wound spools ensures the best performance and prevents tangling.