Robot mowers are expensive to buy and cheap to run. Here’s what the running costs actually come to, so you can weigh it against what you spend now.
Electricity
This surprises people. A robot mower draws very little — they’re low-powered machines that work slowly rather than powerful ones that work fast. Over a full UK cutting season, roughly March to October, expect somewhere in the region of £10–£25 depending on lawn size and how often you run it.
A larger machine covering 2,000m² several times a week sits at the top of that range. A small mower on a town garden sits at the bottom.
Blades
The real consumable. Robot mowers use small razor-like blades rather than one large rotating blade, and they need replacing every one to three months in the growing season. A pack costs a few pounds and takes about five minutes to change with a screwdriver.
Budget £20–£40 a season. Sandy soil and lawns with a lot of leaf litter wear blades faster.
Winter storage and servicing
Bring the mower indoors over winter — a garage or shed is fine. Clean the underside, charge the battery to about half, and leave it. That costs nothing.
Batteries last around four to six years before capacity drops enough to notice. A replacement is typically £100–£200. Spread over that lifespan it’s a modest annual figure, but it’s the one cost people forget when comparing against a petrol mower.
The rough annual figure
For a typical family garden: somewhere around £50–£80 a year including electricity, blades and a share of eventual battery replacement.
Set that against petrol, oil, annual servicing, and the value of an hour a week from March to October. Most people find the running costs are not the deciding factor — the purchase price is.
Figures are indicative estimates for guidance, based on typical UK domestic use. Your actual costs will vary with electricity tariff, lawn size, grass type and how often you run the machine.