How tall a ramp does your robot vacuum need?

Your sill minus the robot’s rating: the ramp has to make up the rest.

Updated Oct 30, 2026.

How do I work out the ramp height?

Measure the sill from the floor on the lower side to its highest point (how to measure), find the robot’s figure in the table or on door sills, and subtract. The table rounds up to the next quarter inch and gives the least the ramp has to make up. The makers rate a step on a flat floor, not one at the top of a ramp, and the ramp’s own front edge is a small step too, so a ramp that reaches the top of the sill is the safer choice. If the robot crosses both ways, it needs a ramp on each side.

Are the makers’ figures the same thing?

Not quite. Most makers give a single-sill height; four of the robots here have a figure for crossing obstacles instead, marked in the table. Some also give a higher figure for two steps or stacked sills, with conditions such as how far apart the steps are: see door sills for each figure and its conditions. A two-step figure is not one step that tall.

Does anyone measure what robots actually climb?

The makers’ figures are ratings, not our measurements; we don’t test robots. Vacuum Wars, a review site, runs its own climbing test: it starts each robot at ¾ in (19 mm) and adds a quarter inch at a time until the robot can’t cross a single threshold (page updated Oct 8, 2026). See Vacuum Wars’ threshold climb test.

Four of the robots here have no published sill figure: the Dreame D20 Plus, the Narwal Freo Z10 Turbo, the eufy Auto-Empty C10 and the iRobot Roomba Max 705 Vac.