How to read a robot mower spec sheet

The first line on every sheet, and the one that decides which yards a mower can work in. A boundary wire is a perimeter loop pinned or buried around the lawn; the mower senses its field and turns. It works under trees and along walls, costs an afternoon to lay, and is cut by aerators and edgers. RTK GPS uses a reference antenna to correct the mower’s satellite fix to about two centimeters, so the boundary is a line you draw in the app; it needs open sky at both ends. RTK + Vision adds cameras so the mower keeps working through short shaded stretches.

Vision-only mowers navigate by recognizing grass through a camera: no wire, no antenna, but daylight only and no precise virtual boundaries. LiDAR mowers build a 3D laser map and position against it, which works under canopy and at night. UWB beacon mowers use corner posts for a local positioning grid. The catalog currently splits 7 RTK GPS, 12 Boundary Wire, 19 RTK + Vision, 6 Vision Only, 9 LiDAR; 41 of the 53 are wire-free. The navigation guide compares them by what breaks each one.

The maker’s figure for a simple, open lawn with the mower running most of the day on most days. Real yards have islands, narrow passages, slopes, shade, and charging gaps, all of which eat into it. From the Gardena SILENO minimo at 2,700 sq ft to the Yarbo Lawn Mower Pro at 269,098 sq ft, every number on this sheet is an upper bound.

Measure the grass, not the lot (a quarter-acre lot often holds 5,000-7,000 sq ft of actual turf), then buy a rating 30-50% above it. One acre is 43,560 sq ft; the catalog shows both units because makers rate small mowers in square feet and large ones in acres.

Makers quote slope as a percentage — rise divided by run — and it diverges from degrees quickly: 25% is about 14 degrees, 45% is 24, 80% is 39. The rating is measured on dry grass in the interior of the lawn. At the boundary, where the mower has to stop and turn on the slope, the published limit is usually about half the headline, and wet grass, clay, or a freshly aerated lawn cuts both figures further.

Rear-wheel-drive mowers cluster at 20-35%; the Lymow One Plus at 100% is all-wheel-drive or tracked, as is everything above about 45%. The slope guide has the table.

How much lawn disappears per pass. Robot mowers are narrow by design — 6.2 to 20 inches across the catalog, against 21 inches for a typical walk-behind — because they make up for it by mowing daily. Width matters mostly as a proxy: a wider deck is a bigger, heavier machine with a bigger battery and a larger rated area. It also decides the minimum passage the mower can work through, which is roughly the deck width plus turning room.

The range the blade disc can be set to. Robot mowing grew up on short European cool-season turf, and much of the catalog still tops out around 2.4 inches. Kentucky bluegrass and ryegrass are happy there. Tall fescue wants 3-4 inches and St. Augustine and Zoysia 2.5-4, so a low maximum means scalping those lawns every day. The Yarbo Lawn Mower Pro reaches 4 inches; several makers sell high-cut variants for exactly this reason.

Most mowers cut with small pivoting razor blades on a disc, which mulch fine clippings back into the turf and wear out in a month or two of daily use. Set the height high for the first two weeks and lower it a notch at a time.

12 of the 53 mowers are all-wheel drive; the rest drive the rear wheels and pivot on front casters. On a flat lawn the difference is invisible. On a slope over about 15-20%, on wet or clay soil, or where the boundary sits on the slope, AWD is the spec that keeps a mower climbing instead of spinning, holds a straight line across a hill, and turns at the edge without sliding out of bounds. It also adds weight, cost, and a second set of motors to maintain.

Runtime is minutes of mowing per charge; charge time is minutes back on the dock. The ratio between them, multiplied by the hours in the schedule window, is what actually produces the rated lawn size: a mower that runs 120 minutes and charges for 90 covers far more than one with the same runtime and a two-hour charge. Runtime falls in tall or wet grass and on slopes, and the battery loses capacity over three to six seasons.

Robot mowers run between roughly 54 and 65 decibels — a conversation to a dishwasher — against 90-plus for a gas walk-behind. That is what makes daily, early, and late schedules possible without a neighbor complaint. Makers measure at different distances, so treat small differences as noise in the data rather than in the yard.

How the mower avoids what isn’t grass. A bumper is the floor: the mower drives into things gently and backs off. Ultrasonic sensors slow it before contact. Cameras with object recognition stop for people, pets, and furniture and are mediocre at hoses and small toys. LiDAR sees obstacles in 3D and is the best of the four, including in the dark. Every class has lift and tilt sensors that stop the blades instantly; obstacle detection is about not needing them.

Every mower pairs over Bluetooth for setup and most join home Wi-Fi for scheduling and status. 35 of the 53 carry built-in 4G, which is what enables GPS theft tracking, geofence alerts, and control from anywhere, and what keeps the mower reachable at the far end of a large lawn beyond Wi-Fi range. Some brands include cellular for years on premium models, others bundle a year and charge afterward, some sell the module separately; the spec table on each mower page records the terms.

Every mower in the catalog has a PIN lock and a lift alarm, and a stolen mower is useless without its PIN and its own base station. The cellular models add GPS tracking and an alert when the mower leaves a geofence. The realistic risks are lower than the forums suggest: a base station in reach of the sidewalk, and a mower that wanders when a boundary fails.

Robot mower warranties run one to three years for the machine and often less for the battery and blades, with dealer-sold brands at the long end. Read the split terms: batteries are frequently covered for a shorter period or a cycle count, and some makers require registration within a window. A longer warranty matters more here than on a gas mower, because the failure modes are motors and boards, not belts.

Every price on this site is a hand-maintained snapshot from our last catalog update, marked approximate because robot mower pricing moves hard with season and launch cycles — spring launches and fall clearances can differ 30% on the same machine, and DTC brands run frequent promotions. The retailer’s price at checkout is the real one; see how we compare for how the site makes money and the cost guide for what the sticker leaves out.