Best 20V Cordless String Trimmers: Six Tool-Only Picks That Reuse Your Power Tool Batteries

Introduction

If you already own a stack of cordless power tool batteries, a string trimmer that runs on the same platform is one of the most practical yard upgrades you can make. Instead of buying into a separate outdoor battery system, you simply put the batteries sitting in your shop to work in the backyard.

One clarification before we start: 20V max and 18V are effectively the same thing. The “20 volt max” label is a marketing convention based on how the cells are rated, while the actual nominal voltage of five cells is 18 volts. So a 20V trimmer will run on the same class of battery you already own, whichever way the brand writes it on the label.

There is one trade-off worth considering. Power tool batteries are typically rated for a limited number of recharge cycles, so using them for regular yard work adds wear. Brushless motors help here: they deliver more power and better run time, which means fewer battery swaps and less strain on your battery pool.

Evaluation Criteria

For this category, the priorities are simple. A tool-only price that makes sense when you already own batteries, brushless efficiency where possible, cutting width, and extras such as attachment capability or an edging head. Runtime and power matter too, but most of these trimmers are aimed squarely at average-sized yards, not large acreage.

Best Budget Entry: Bauer 20V String Trimmer

Bauer’s basic handheld 20V string trimmer is about as simple as this category gets. It takes your standard 20V battery and, at around $55 tool only, is one of the cheapest ways to add a trimmer to an existing battery system. Even this entry-level model has a rotating head for edging, complete with small wheels that let you roll along the edge as you work.

This is the pick for anyone who wants the lowest possible entry fee and does not need serious cutting power. It will handle routine trimming around an average yard, and nothing more.

Best All-Round DIY Pick: Ryobi ONE+ 18V Brushless

Ryobi has long been the go-to brand for DIY outdoor power equipment, and this 18V brushless 15-inch trimmer shows why. It is attachment capable, meaning the head in the middle of the shaft can be removed and swapped for other attachments such as hedge trimmers or blowers, which makes the tool more versatile and stretches your dollar further across the platform.

At $102.38 tool only, it pairs a reasonable cutting width with the flexibility of the huge ONE+ ecosystem. This is the sensible default for most homeowners.

Best Brand Loyalty Play: DeWalt 20V Brushless String Trimmer

DeWalt’s brushless string trimmer runs on the standard 20V platform, so it takes the same batteries as your DeWalt hand tools. At $159 tool only, it is clearly aimed at contractors and serious DIYers who want to keep everything on one battery system.

Brushless power and good runtime are the main draws. If your tool collection is already yellow, this is the low-friction way to bring the yard into the same fold.

Best Prosumer Value: Kobalt 24V Brushless String Trimmer

Kobalt’s 24V brushless trimmer is arguably the strongest value in this roundup. It is not sold tool only, but at $149 list you get the trimmer, a charger, a 2Ah battery, and a bonus 4Ah battery with no discount required. If it ever goes on sale, the value gets even better.

In use, it is a solid trimmer for around-the-house work. It is not as powerful as a 40V-class machine and will not take down four-foot grass, but for trimming a normal yard it does the job well.

Best Dual-Battery Option: Makita LXT X2

Makita takes the 18V idea and doubles it. This trimmer uses two 18V LXT batteries simultaneously to deliver 36V-class performance, so you can run it off the same batteries you already use with the rest of the LXT line. It is a clever way to get 40V-level power without buying into a separate battery system.

At $269 tool only, it is a premium choice, but for anyone already invested in Makita’s LXT platform it is one of the most capable cordless trimmers in this class.

Best Upgrade Path: DeWalt FlexVolt 60V String Trimmer

The FlexVolt 60V max trimmer is the outlier here: it will not run on standard 20V batteries and requires a FlexVolt pack. The appeal is for users who already own a FlexVolt battery for their hand tools, since it lets that battery pull double duty in outdoor power equipment.

If you are starting fresh, this is more power than the average yard needs. But if you are already in the FlexVolt ecosystem, it is a natural upgrade.

Buying Advice: Matching Power to Your Yard

These 18V and 20V systems are designed for average-sized yards. If you are maintaining a small suburban lot and already own batteries, a tool-only brushless trimmer is the sweet spot: good power, longer runtime, and no new charger to buy. The Bauer covers the absolute cheapest route, while the Ryobi adds attachment versatility.

If you want more headroom without a new battery line, the dual-battery approach is worth a serious look. Two of your existing batteries effectively become a higher-voltage pack, delivering near-40V performance with hardware you already own. And if a sale comes around with bonus batteries included, that can tip the math heavily in favor of a kit over a tool-only purchase.

Conclusion

Reusing your existing power tool batteries for yard work is one of the easiest ways to get more from what you already own. Bauer wins on entry price, Ryobi on versatility, DeWalt on ecosystem continuity, Kobalt on included value, and the dual-battery options deliver the most cutting power without a separate battery system. Match the tool to your yard size and battery lineup, and you can skip buying a whole new platform entirely.