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That "up to 1/2 acre" robot mower is rated for an easy lawn
The area on a robot mower box is a best case: an open lawn, mostly flat, in one piece. Husqvarna even lists its own lawn sizes as plus or minus 20 percent. Add trees, flower beds, a narrow side yard, a slope and a second zone, and a typical "1/2 acre" mower handles more like 14,800 sq ft by our rule of thumb.
Robot mower capacity check
This is an estimate. The layout, slope and zone factors are our own rule of thumb, not a maker figure. Husqvarna lists its own lawn sizes as plus or minus 20 percent, which is where the 0.8 for a yard with trees and beds comes from. We plan to use no more than 80 percent of the adjusted capacity, to leave room for rain days and fast spring growth.
Check your yard in a minute See the 6 mowers we'd shortlist
Box claimTypical yard estimate
- Husqvarna 410iQ21,780 sq ft14,800 sq ft
- ECOVACS GOAT A200021,780 sq ft14,800 sq ft
- WORX WR32021,780 sq ft14,800 sq ft
- Mammotion LUBA mini 216,117 sq ft11,000 sq ft
- Navimow i105N5,445 sq ft3,700 sq ft
- Gardena SILENO City2,700 sq ft1,800 sq ft
Four things listings do not make clear
- Area. The rated area assumes an easy lawn. Plan to use about 80 percent of what is left after you adjust for your yard.
- Slope. "45% slope" means 45 feet of rise per 100 feet, about 24 degrees, and many makers allow much less at the edge of the lawn. See slope ratings explained.
- Setup hardware. Wire models need a wire laid around every edge. Some wire-free models need an antenna or reference station mounted with a clear view of the sky. See wire vs RTK vs vision.
- Theft and cellular. Some tracking needs an add-on 4G module or a data plan. See theft, rain and 4G.
Safety, every time it runs
- Kids and pets off the lawn while it mows. Obstacle sensors and cameras reduce the risk. They do not remove it. Schedule mowing for times when nobody is playing outside.
- Never lift or tip it while it is on. Stop it and turn it off first. Wear gloves when you change blades.
- Check for recalls. Search your model on CPSC.gov and register the mower with the maker so they can reach you.
- Read the manual's safety section. It is the only place that covers your exact model.
Guides
- The 6 best robot lawn mowers, sized for a real yard
Six robot mowers from Husqvarna, Mammotion, ECOVACS, Segway Navimow, WORX and Gardena, compared by the lawn they can really handle, slope, setup and cutting height.
- How much of that robot mower would your yard use?
Enter the area on the box and your lawn. Adjust for trees, slopes and zones to see what share of the mower you would use, plus mowing hours per week.
- What "up to 1/2 acre" means on a robot mower
Robot mower area claims assume an open, flat lawn in one piece. How trees, zones and grass growth shrink it, and how much headroom to leave.
- Robot mower slope ratings, explained
A 45% slope is about 24 degrees, not 45. How to read robot mower slope claims, why the lawn edge has a lower limit, and which picks climb most.
- Wire, RTK or vision: what you have to install
Boundary wire, RTK with an antenna, cloud RTK, LiDAR and cameras: what each robot mower needs installed, and how trees and shade affect it.
- Cutting height on a robot mower
Robot mower cutting heights run from about 1 to 4 inches. Which range suits your grass, why the first cut needs a regular mower, and how each pick adjusts.
- Theft protection, rain and 4G on a robot mower
Which robot mowers have an alarm, GPS tracking or 4G, which need an add-on module, and what IP ratings and rain claims really tell you.
- Robot mower safety with kids and pets
Robot mowers have real blades. The ANSI/OPEI safety standard, how obstacle sensing works, and simple rules for homes with children and pets.