Start from your house, not the spec sheet

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  Half acre, no wire

  The best robot lawn mower for a half acre with no perimeter wire

  A half-acre lawn, one continuous piece, a slope you notice when you push a mower up it, and no wire you are willing to bury. Every robot mower we track, judged against that yard from the limits its own maker publishes.

  For a half-acre lawn with a 20% slope and no buried wire, the Greenworks AiMowbot C40 is the pick: it clears both limits that decide this page with margin, and its $1,500 is the lowest list price of any fitting unit whose maker publishes one; it is also the only pick with no verified Amazon listing, so that figure is Greenworks' own asking price rather than one you can pay in a cart today.

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  Small yard

  The best robot lawn mower for a small yard

  A small suburban lawn, a gentle grade, and a couple of beds to steer around. Almost every robot mower we track clears a yard this size, so the question stops being which one is big enough and starts being which one is worth what it costs.

  For a small lawn (3,000 sq ft) with a 15% slope, the Segway Navimow i105N is enough mower and the cheapest way to get there: Segway rates it for 5,445 sq ft and a 30% slope, both well past what this yard asks of it.

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  Inground pool

  The best robotic pool cleaner for an inground pool

  An inground pool of ordinary size, with walls that need scrubbing as much as the floor does. Every robotic cleaner we track, judged against it on the pool length and wall climbing the makers publish, and then on what independent testers found when they ran the machines.

  For an inground pool 35 feet long, walls included, the Dolphin Nautilus CC Plus is the pick: Maytronics builds it for a pool set in the ground, rates it for one up to 40 ft, and states that it scrubs floor and walls in a single cycle, so this pool sits inside every published limit with room left.

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  Above-ground pool

  The best robotic pool cleaner for an above-ground pool

  An above-ground pool 24 feet across, on a soft liner, with a wall you can reach over. The maker's own pool-type rating decides this page before anything else gets a say: it rules out 4 of the 13 cleaners judged here on its own.

  For an above-ground pool 24 feet across, the Dolphin E10 is the unit built for this pool: Maytronics rates it for above-ground use to 30 ft, and Popular Mechanics named it Best for Above Ground Pools, saying its scrubbing is effective but gentle enough not to damage a softer liner.

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  Three cats

  The best automatic litter box for multiple cats

  3 cats, one of them big and one of them small, and one box that has to serve all of them. Two published limits decide it: the number of cats the maker rates the box for, and the weight range its sensors were built around.

  For 3 cats between 6 and 16 pounds on clumping litter, the Whisker Litter-Robot 4 clears every limit Whisker publishes, with the widest weight range of the three picks.

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  Pet hair, hard floors

  The best robot vacuum for pet hair on hard floors

  A shedding dog or two cats, hard floors through most of the house, low thresholds between the rooms, and a wish that the bin emptied itself. Every robot vacuum we track, judged against that house from the limits its maker publishes rather than from a lab's dust-pickup score.

  For a house with hard floors, 15 mm thresholds, a shedding pet and a wish for both a mop and a dock that empties itself, the eufy X10 Pro Omni clears the limits for the least money and is the only pick with a named tester's measurements behind it, the Narwal Freo X10 Pro adds a mop that lifts clear of a rug and a dock bag Narwal will put a figure on, and the Narwal Freo Z10 Turbo adds the highest published suction on the page and very little else that is published.

Every page carries an “adjust to my house” box that re-judges the picks on your own numbers. Every robot we track.