DeWalt DCMAST561 vs Ryobi RLT1831

Put these two side by side and the spec sheets look almost interchangeable: both are 18V, line-only cordless trimmers aimed at the same job — keeping grass and edges tidy, not clearing scrub. The DeWalt DCMAST561 leans on DeWalt’s XR brushless platform and trade-grade build. The Ryobi RLT1831H25F leans on the sheer size of Ryobi’s ONE+ battery ecosystem instead. Neither will touch brambles or woody stems, so if that’s what you’re facing, this comparison isn’t the one you need. But for grass, weeds and borders, the choice between them mostly comes down to which battery family you already own — or want to start owning.

At a glance

	DeWalt DCMAST561	Ryobi RLT1831H25F
Power system	18V XR, brushless motor	18V ONE+
Cutting attachment	Line only, no blade option	Line only, no blade option
Cutting width	33 cm	25-30 cm
Handle	Loop handle	Loop handle plus second handle
Weight class	Light to mid-weight	Light, one-handed friendly
Battery platform	DeWalt 18V XR (trade tool range)	Ryobi 18V ONE+ (one of the largest ecosystems)
Supplied	Commonly bare tool	Commonly bare tool

The real fork in the road: which battery ecosystem

This is where the comparison actually gets decided, more than any trimmer-specific feature. DeWalt’s 18V XR platform is a genuinely trade-oriented battery family, shared with drills, saws and other job-site tools — a natural fit if you already lean on DeWalt kit for proper work. Ryobi’s ONE+ system, by contrast, is one of the broadest cordless ecosystems sold anywhere, stretching from drills and blowers to pressure washers and well beyond typical garden tools, aimed squarely at DIY households wanting one battery pool for almost everything. Neither ecosystem is “better” in the abstract; it’s about which one you’re already invested in, since both trimmers are frequently sold bare and the battery you already own decides the real cost far more than the tool price does.

Build, width and handling

The DeWalt DCMAST561 has the edge on outright build quality — its brushless motor should outlast a brushed equivalent, and the housing and trigger feel closer to a trade tool than a garden-centre disposable. Its 33 cm cutting width also covers open lawn a little faster than the Ryobi’s 25-30 cm head. The Ryobi RLT1831H25F answers with a lighter build that’s easier to swing one-handed on smaller plots, plus a second handle that steadies longer sessions and awkward angles — a detail the DeWalt’s simpler loop handle doesn’t offer. If you’re mostly edging borders and tight corners, the Ryobi’s narrower head and extra handle can actually feel more manageable than the DeWalt’s slightly wider, single-handle setup.

Runtime and everyday use

Both trimmers sit in the same “adequate for regular maintenance, not generous for a big overgrown plot” bracket typical of 18V line trimmers. Neither is going to match a petrol strimmer’s all-day stamina, and both benefit from having a spare battery on charge if your garden is on the larger side. Maintenance is simple on both — feed line, trim, repeat — since neither has a blade guard or blade sharpening to worry about. Where they diverge slightly is in feel: the DeWalt’s brushless motor tends to hold power more consistently as the battery depletes, while the Ryobi’s lighter overall weight makes it less tiring to carry through a long edging session, even if outright power delivery is a notch behind.

Choose the DeWalt DCMAST561 if…

• You already own, or plan to build, a DeWalt 18V XR battery collection for drills, saws or other trade tools
• You want the wider 33 cm cutting width for covering open lawn a bit faster
• Brushless motor longevity and a more trade-grade build matter to you
• You’re happy with a simple loop handle rather than a second steadying grip

Choose the Ryobi RLT1831H25F if…

• You already own, or plan to invest in, Ryobi’s sprawling 18V ONE+ ecosystem across drills, blowers and more
• You want a lighter tool that’s easy to swing one-handed on a smaller plot
• The second handle for steadier two-handed control on longer sessions appeals to you
• Tight borders and narrower spots matter more to you than covering wide lawn quickly

Which should you buy?

If you’re already carrying DeWalt 18V XR batteries, or you want the closest thing to a trade-grade line trimmer with a wider cutting swath, the DeWalt DCMAST561 is the sensible pick — its brushless motor and 33 cm width edge out the Ryobi on raw cutting capability. If you’re sitting on Ryobi ONE+ batteries already, or you value a lighter tool with a second handle for control on tighter ground, the Ryobi RLT1831H25F does the same core job at a similarly light-duty level, with the huge ONE+ ecosystem behind it.

Either way, remember both are commonly sold as bare tools, and neither one accepts a metal blade — so if brambles or woody growth are part of your garden’s story, look elsewhere on both brands’ ranges rather than expecting either of these to stretch beyond grass and edges.