Menu

Robot mower and robot vacuum sizing

The right robot for your lawn and your floors.

Enter your lawn or floor numbers and Botsize shows which robots fit, which are tight and which do not, with the math.

Size a robot mower

Grass only. Leave out the house, the drive and the beds. Work it out from shapes

Steepest part of the lawn

Turn a rise and a run into a slope

For floors, the vacuum finder checks thresholds, furniture height and the dock.

Plan of an example lawnA lawn 32 m long and 25 m wide with a tree and a flower bed, drawn on a measuring grid. A robot mower is part way through its stripes.32 m (105 ft)25 m (82 ft)
Lawn
32 × 25 m = 800 m²8,610 sq ft
Shape
typical, × 1.35
Mowing hours
any time, × 1
Rating it needs
1,080 m²11,630 sq ft
Steepest slope
15% (8.5°)clear pass from a 20% rating
A worked example. The sizer runs the same arithmetic on your numbers.

Specifications checked . Every model page lists its sources and the date each one was read.

Three steps from your lawn to a short list

  1. Measure

    Enter the area of grass and the steepest slope the mower has to climb. Square feet, acres and square meters all work.

  2. Add the margin

    A rating does not say how much beds, corners and short mowing hours cost, so the sizer adds a margin, a rule of thumb. It multiplies your area by 1.2 for an open lawn, 1.35 for a typical one and 1.5 for a complex one, and by 1.5 again when the mower may only run in daytime.

  3. Compare with each rating

    A model whose rating covers the margin fits. One that covers the lawn but not the margin is tight. One rated below the lawn itself does not fit.

An 800 m² (8,610 sq ft) lawn of typical shape needs a rating of 1,080 m² (11,630 sq ft).
  • FitsRated 1,200 m² (12,920 sq ft)120 m² (1,290 sq ft) above the 1,080 m² (11,630 sq ft) it needs
  • TightRated 1,000 m² (10,760 sq ft)covers the 800 m² (8,610 sq ft) lawn, 80 m² (861 sq ft) short of the margin
  • Does not fitRated 700 m² (7,530 sq ft)100 m² (1,080 sq ft) short of the lawn itself

Robot vacuums: thresholds, furniture and the dock

The vacuum finder compares the tallest threshold between your rooms with the climb height each maker publishes, and your lowest furniture with the height of the robot. It checks whether the dock empties the bin or washes the mop, and whether the mop lifts off carpet.

A 20 mm (0.79 in) threshold passes cleanly from a 22 mm (0.87 in) climb rating. A sofa with 95 mm (3.74 in) of clearance takes a robot up to 90 mm (3.54 in) tall.

Open the vacuum finder
Side view of a robot vacuum under a sofaA robot 90 mm tall passes under a sofa with 95 mm of clearance and heads for a 20 mm threshold.95 mm20 mmrobot 90 mm tall

Common starting points

Each link opens the answer worked out for that lawn or home, with a link to change the numbers.

Lawns

Floors

Or browse every robot mower model by rated area, slope limit and price, and every robot vacuum model by threshold climb, height and price.

Where the numbers come from

Every rating, slope limit, threshold and price comes from the maker's own pages, with the date we read them. Botsize does not test robots. It reads the specifications and does the math, and the methodology states every factor. Links to makers may earn a commission one day. That never changes a result: see how we make money.