Botsize ran every robot mower in its dataset through the sizer for a half acre lawn of typical shape. The verdicts below follow your region, and each card shows the numbers behind its verdict.
Updated
Change these numbers in the sizer, or read how the shape and hours factors work in the methodology. They are rules of thumb.
Of the 33 mowers sold in the US: 16 fit, 2 are tight and 15 do not fit.
Closest fit first: the smallest limit that still covers the rating your lawn needs, then the lower price, then the larger slope margin.
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The limit covers the rating your lawn needs, and nothing rules the model out.
ECOVACS
MAMMOTION
Sunseeker
Needs an antenna at home and open sky over the lawn.
Dreame
Husqvarna
Needs a boundary wire laid around the lawn.
The limit covers your lawn but not the margin, or the slope is at its limit.
Roborock
Husqvarna
Needs antenna: not stated and open sky over the lawn.
This page ranks the 33 mowers in the Botsize dataset that are sold in the US. Prices are the maker's list price, or the price its page showed that month (sometimes a sale price), with the month we read it.
To work out your own lawn size, the lawn area calculator adds up the shapes of your garden.
Half an acre is 21,780 sq ft (2,023 m²). For this lawn that means 26,136 sq ft (2,428 m²) on one open shape, 29,403 sq ft (2,732 m²) with some beds and trees, and 32,670 sq ft (3,035 m²) for a complex layout. A mower allowed to run in daytime only needs 1.5 times as much again: 44,105 sq ft (4,097 m²) for a typical shape.
At this size the layout starts to matter as much as the area. A half acre may split into a front and a back lawn joined by a side strip. Count the separate lawns and enter them in the sizer: a model whose maker says it handles one area only does not fit several. Measure the narrowest point on the way between them, such as a side gate, and compare it with the passage width on each model page.
With a boundary wire, every edge and bed of a half acre needs wire, and the perimeter of a square half acre alone is about 590 ft (180 m) before the beds. Wire-free models trade that work for other needs: open sky for satellite models, fixed objects to measure against for LiDAR. The wire and wire-free guide compares them.