Best Cordless Lawn Mowers UK: Buying Guide

Cordless lawn mowers have taken over from petrol and corded models in most UK gardens, and for good reason — no fuel, no trailing cable, and modern batteries now cut lawns that would once have needed a petrol mower. But "cordless" covers a huge range of machines, from small 18V mowers built for tiny courtyard lawns to 80V+ mowers that rival petrol on power. Here's what actually matters when you're choosing one.

Battery voltage and amp-hours

Voltage roughly determines cutting power, and amp-hours (Ah) determine runtime. A 36V battery with 4Ah will run longer than a 36V battery with 2Ah, and a mower with two batteries doubles your runtime without doubling the price of a bigger single battery.

As a rough guide:

• Under 250m² (small/courtyard lawn): 18–20V is usually enough
• 250–500m²: 36V (or twin 18V) is the sweet spot for most UK gardens
• 500m²+ or thick/overgrown grass: 40V–80V, or consider that a cordless mower may need a battery swap mid-cut

Always check runtime in minutes, not just voltage — manufacturers test this on flat, dry, short grass, so real-world runtime on a lumpy or damp lawn will be shorter.

Cutting width

Cutting width determines how many passes you need. A 32cm mower is fine for small, fiddly lawns with lots of borders to work around; a 40–46cm mower covers a medium lawn much faster but is heavier and harder to manoeuvre in tight spaces. Match the width to your lawn's shape, not just its size — a long, narrow lawn benefits less from a wide mower than a square one does.

Cutting height and grass box

Look for at least 5–7 height settings so you can raise the blade during a summer dry spell (cutting too short stresses the lawn and encourages moss and weeds). A single-lever height adjustment is far more usable day-to-day than adjusting each wheel individually.

Grass box size matters more than people expect — a small 30L box on a wide mower means constant stopping to empty it. If your mower supports mulching (cutting grass fine and dropping it back into the lawn as feed), that's worth having for the drier months when you're cutting less often anyway.

! Battery-swap tip: if you already own another cordless tool — a hedge trimmer, strimmer or drill — check whether the mower uses the same battery platform. Buying "bare" (mower only, no battery) on a platform you already own is often significantly cheaper than a bundled kit.

Weight and storage

Cordless mowers are generally lighter than petrol equivalents, but battery packs still add weight, especially on twin-battery models. If you're storing it in a shed up steps, or you have limited upper-body strength, check the mower's weight (not just the box's headline spec) before buying — some manufacturers quote weight without the battery fitted.

A quick pre-purchase checklist

• Lawn size and shape (measure it — most people overestimate)
• Runtime in minutes, at the voltage/Ah combination you're actually buying
• Cutting width suited to your borders and gates
• Number of height settings and how easy they are to adjust
• Grass box capacity, and whether mulching is supported
• Battery platform — does it match tools you already own?
• Weight, including the battery

Specs matter, but price varies a lot between retailers for the exact same model — sometimes by £40–£80 on an otherwise identical machine. Once you've picked a spec, compare live UK prices across retailers on GrowMuir rather than buying from the first listing you find.