Best cordless lawn mowers UK: our honest pick, and what else is out there

Our pick: the Ryobi 18V ONE+ OLM1833B

A 33cm cutting width with a single-lever height adjustment across 3 positions (some reviewers describe it as stiff at the highest setting), a 35L grass box, and a mulching plug included if you'd rather not collect. Ryobi markets an "EasyEdge" grass comb for cutting close to a wall or fence, though that term doesn't actually appear in the official manual, so treat it as retail description rather than a documented mechanism.

The manual gives real mechanical specifics most listings don't: a no-load blade speed of 4,400 revolutions a minute, a single replaceable blade (part RAC434), and an explicit warning not to mow slopes steeper than 15 degrees, mowing across the face of a slope rather than up and down. It's hand-propelled, not self-propelled, and the handle folds only at the mid-point rather than flat to the deck, so it's compact for storage but not a full flat-pack fold.

It's part of Ryobi's 18V ONE+ platform, the same battery that runs the other 11 Ryobi tools this site curates, and like most of them it's sold bare-tool by default, battery and charger excluded.

How much garden can it actually cut?

Worth being upfront: Ryobi's own figures for this exact mower don't agree with each other. The official spec-comparison chart states 180m² on a 4.0Ah battery and 225m² on a 5.0Ah battery, tested on 80mm grass cut down to 40mm at an average walking pace. But the 5.0Ah kit's own separate product page states 150m² in its body copy, a genuine internal contradiction on Ryobi's own site, not a typo we're inventing.

An independent review measured closer to that lower figure in practice: around 150m² and 30 minutes of continuous cutting on a 4.0Ah battery, dropping to 15-20 minutes on a 2.5Ah battery. Their own advice, based on that testing: buy at least a 4.0Ah battery, and a 5.0Ah if you can, rather than starting with anything smaller.

Grass condition swings this further. Ryobi's manual explicitly warns against cutting wet grass at all, since clippings stick to the deck's underside instead of reaching the box. One real UK account describes cutting dry, short grass for 45 minutes on a single charge, well past the lab figures; others describe successfully clearing overgrown grass over 6 inches high, at the cost of runtime. No source publishes a verified coverage figure for this mower on anything smaller than a 4.0Ah or larger than a 5.0Ah battery, so don't trust a number you see quoted for a 2.0Ah or 6.0Ah pack on this model specifically.

Bare tool vs kit: the real ONE+ ecosystem economics

Checked live on Ryobi's own UK site on 2 August 2026: the bare OLM1833B is £127.49 (reduced from £177.99), a 4.0Ah battery-and-charger kit is £99.99, and a 5.0Ah kit is £102.00. Buying the mower from zero costs £227.48 to £229.49 depending which kit you add. Already own a compatible ONE+ battery from another tool, and you only pay the £127.49, a saving of almost exactly £100, or around 45% off the from-zero total.

That saving compounds across Ryobi's own stated 200+ tool ONE+ range, and there's a live example of it right now: Ryobi UK is running a promotion (checked running until 4 October 2026, or while stocks last) where buying that same £99.99 4.0Ah kit gets you a second bare ONE+ tool free from a list of 30. We couldn't confirm whether this mower is on that eligible list, so don't assume it is, but it's real evidence of how the platform is designed to reward buying in once.

Those are Ryobi's own direct prices, not necessarily what this site's own Amazon-checked listing shows on a given day. For today's actual price to buy through, see this site's own Ryobi deals page.

Assembly and what to expect the first time you use it

A real UK buyer, posting on a Ryobi forum, reported assembly taking around 10 minutes, faster still if you already own other Ryobi tools since you're not unboxing a battery and charger too. They also flagged the wheel height-adjustment mechanism as feeling "flimsy" to operate, echoing a separate independent review's note that the lever "can be stiff" at the highest settings, a genuine, recurring complaint worth going in expecting.

The mulching plug ships pre-installed and needs removing before you can fit the grass box, and fitting that box is the one step reviewers consistently call "a little tricky at first" until you're used to it. If buying the kit rather than bare, budget around 2 hours to fully charge the bundled battery before that first cut.

For a genuinely overgrown first cut, start at the highest height setting and work down in passes rather than trying to take it all off in one go, both to protect the lawn and to make the most of one charge.

Weight, storage and maintenance over a season

Sources disagree on weight, so we're stating the range rather than picking whichever flatters the page: Ryobi's own manual states a net bare-tool weight of 7.5-7.7kg (two different copies of the same manual give slightly different figures), while retailer listings and reviews range from 8.7kg to 9.9kg, and a full kit with battery and charger has been quoted as high as 13kg. The higher figures almost certainly include the battery, charger or packaging rather than contradicting the manual's bare-tool number.

Ryobi's own guidance for storage is plain: remove the battery, and store somewhere cool, dry and out of children's reach. The handle and grass box are both described as removable/collapsible for compact storage, though we couldn't confirm a "stores fully upright" claim from the manual, so don't assume that specifically.

On maintenance, Ryobi doesn't publish a fixed sharpening or replacement interval, its own guidance is inspect-and-replace-if-damaged rather than a schedule. The blade itself is a genuine spare part (RAC434, £10.25 on Ryobi's own site). No credible source publishes a real capacity-degradation figure for 18V ONE+ batteries specifically, several sites quote generic lithium-ion percentages with no Ryobi data behind them, so treat any specific number you see elsewhere as unverified. What is concrete: a genuine replacement 5.0Ah battery is £99.99, carrying the standard 3-year warranty rather than the 6-year cover you get on the tool itself by registering within 30 days.

Grass collection vs mulching for a UK lawn

The RHS's own default guidance is to collect, emptying the box regularly, with mulching treated as a conditional technique rather than a permanent setting. Its genuine benefit is real: finely chopped clippings return nitrogen to the soil and help retain moisture as they break down, and clippings aren't the main cause of lawn thatch either, that's mostly built from roots and stems, not grass cuttings.

The catch is that it only works cleanly on grass that's cut short and mown regularly. Let growth get away from you, or mow while it's still wet, and the clippings clump on the surface instead of dispersing, at which point collecting that one pass is the better call (and matches Ryobi's own manual warning against cutting wet grass at all). A common seasonal pattern, corroborated across several UK mower retailers rather than any single authority: collect through spring's fast, wet growth, then switch to mulching once summer slows growth down and cuts get shorter and more frequent.

The OLM1833B comes with both a 35L grass box and a mulching plug, so this is a genuine either-way choice on this mower, not one forced by which accessory it ships with.

About this page

LightningBrands curates and price-checks Ryobi's 18V ONE+ range, including the OLM1833B on this page. We don't sell, stock or price-check any of the other brands named above, so their specs are included as honest market context only, sourced from each brand's own site or a named independent reviewer, never dressed up as our own deal or given a price we haven't verified live.

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