How to choose a robot lawn mower

Start with your lawn's size

Every robot mower is rated for a maximum lawn area, usually in square metres in Europe and in acres in the United States (one acre is 4,047 m²). The rating is the most the mower can keep trimmed when it runs on a full schedule, so choose a model rated for more than your lawn: a mower rated for 1,500 m² mows a 1,000 m² lawn comfortably and has time to spare after rain, while one rated exactly for your lawn has to mow almost every day.

Measure only the grass, not the house, patio and flower beds; a mapping app or an online map gives a good estimate. Many ranges come in several sizes with the same design, so the difference between models is often only the battery and the rated area. The robot lawn mower comparison filters every range by lawn size.

Slopes and all-wheel drive

Mowers state their maximum slope as a percentage: the rise over the distance. A 35% slope rises 35 cm over one metre (19°); a 100% slope is 45°. Among the mowers we track the stated maximum runs from 30% to 100%. Two-wheel-drive mowers usually manage 25 to 45%; the 20 all-wheel-drive ranges we list are built for steep banks and hillside gardens, and grip better on wet grass.

Measure your steepest stretch rather than the average, and leave a margin: a mower working at its limit on wet grass can slip and leave tracks.

Wire-free or boundary wire

For twenty years robot mowers followed a wire buried around the lawn's edge. Most new models are wire-free instead: you walk the mower around the lawn once, or draw the edges in its app, and it finds its way by one or more of these:

• RTK satellite positioning (45 ranges): centimetre-accurate positioning from satellites and a reference antenna, ideal for open lawns.
• LiDAR (23 ranges): a laser scanner that maps the garden and keeps working under trees and beside buildings.
• AI vision (50 ranges): cameras that recognise lawn edges, people, pets and objects.

The strongest mowers combine two or three of them. Our guide to RTK, LiDAR and AI vision explains which suits which garden. A boundary wire is still the cheapest way to mark a lawn and works where other systems struggle, but it has to be laid, and repaired when a spade or a mole cuts it.

Obstacles, narrow passages and several lawns

A garden with a front and a back lawn needs a mower that handles several zones and the passage between them: check the narrowest passage it can pass and whether it moves between zones on its own. Trees, garden furniture, toys and animals call for good obstacle detection; mowers with LiDAR or AI vision steer around objects instead of bumping into them, and most have sensors that stop the blades when the mower is lifted.

Edges and cutting height

Robot mowers cut little and often, so the clippings fall back into the lawn as mulch. Check the cutting height range against how you like your lawn: most cut between about 2 and 6 cm, and a few have a high-cut option for longer grass. Mowing right up to the edge is still a weak point; models that cut close to walls and borders save trimming.

Theft protection and connectivity

A robot mower works unattended, often in a front garden. Most models are locked to the owner's account with a PIN, sound an alarm when lifted and, with a mobile data connection, report their position. Wi-Fi covers a garden near the house; a mobile (4G) connection keeps the mower reachable across a large property.

What a robot lawn mower costs

In the United States the mowers we track range from $629 for the Anthbot Pion to $5,999 for the Yarbo Y40 Core. The price rises with the rated area, all-wheel drive and the navigation system; a larger model of the same range often costs only a few hundred dollars more and copes better with a growing lawn or a wet summer.

The same mower is often priced differently in each country: every product page lists the official price in each market where the brand sells it, in local currency.