Robot vacuums and door thresholds: what 20, 42 and 52 mm actually mean
Which robot vacuums climb which thresholds, from the makers' own figures: the 52 mm flagships, the 42 to 45 mm middle, the 20 mm majority, and what the number leaves out.
Maciej Ziółko · RoboVerdict editorial · Published · 4 min read
Why the number matters now
For a decade every robot vacuum climbed about the same step: two centimetres, the height of a rug edge or a low door sill. A flat with a taller sill between the hall and the kitchen got two robots or a ramp. Since 2025 the flagships lift their chassis over a step instead of rolling into it, and the makers now publish the height they clear. That figure is the single most useful number for an older European flat, and it is the one most buyers do not know to look for.
The number is the maker's stated maximum for a single step: one edge, straight on, with the mop lifted or left behind. Below are the figures as published for every machine in our catalogue that publishes one. Roughly four in ten machines we list publish nothing, and their pages say so instead of guessing.
52 mm: the current ceiling
Two machines publish 52 mm, the Dreame X60 Pro Ultra Complete and the Dreame X60 Pro Master, the same robot with a plumbed dock on the Master. The MOVA V70 Ultra Complete and V70 Ultra Complete X publish 50 mm, and the MOVA Z60 Ultra Roller Complete 48 mm, which makes it the highest-climbing roller-mop machine we list.
Dreame X60 Pro Ultra Complete
Dreame's top vacuum: 42,000 Pa, a retracting turret for 89 mm clearance, legs that climb a 5.2 cm sill or a 10 cm double step, a mop pad that reaches 18 cm out and comes off for deep carpet, and a dock that washes at 100 °C, for €1,199.
42 to 45 mm: the flagship middle
Roborock's Saros line is rated for 45 mm across the Saros 20, Saros 20 Neo and Saros 20 Sonic, and so is the Qrevo Edge 3 Pro. Dreame's X60 Max Ultra Complete and X60 Ultra publish the same 45 mm. At 42 mm sit the Dreame Aqua10 Roller, the Aqua10 Ultra Roller Complete, the Aqua10 Ultra Track Complete, the X50 Ultra, the Matrix10 Ultra and the MOVA V50 Ultra Complete. Narwal's Flow, Flow 2 and Freo 20 publish 40 mm, as does the Roborock Qrevo Edge.
Roborock Saros 20
Roborock's flagship: 36,000 Pa, twin spinning mops the dock washes at 100 °C, and a solid-state 3D sensor instead of a LiDAR turret.
20 to 30 mm: what most machines publish
The MOVA S70 Ultra Roller and the Roborock Saros 10 publish 30 mm, the Ecovacs DEEBOT X11 PRO OMNI 24 mm. A large group publishes 22 mm: the MOVA E40 Ultra, MOVA P70 Pro Ultra, Dreame L60 Ultra, L50s Pro Ultra, Matrix10 Pro, L60 Ultra PE and Aqua10 Roller AE. The eufy Omni E28 publishes 21 mm. And 20 mm is the figure for the Roborock QV 35A and QV 35S, the Qrevo S5V, the Q10 X5, the Dreame L40 Ultra Gen 2, D30 Ultra, D30 Ultra CE, L60 Ultra FE, L50 Ultra AE and D20 Pro, the eufy Omni C28, and the MOVA S10 and S10 Plus.
What the figure leaves out
- A rug is not a sill. A thick rug edge is soft and the wheels sink into it; the published height is for a hard step. Most machines cross a 2 cm rug regardless of what they publish.
- Two steps are not one. A sill of 3 cm followed by a raised floor of 3 cm is two climbs, and the second one starts from a slope. The figure describes a single edge.
- Height under furniture is a different question. An 80 mm Saros 20 clears the same 45 mm as a 89 mm X60 Ultra; which fits under your sofa is a second measurement.
- The mop. A machine that lifts its chassis still carries its mop over the step. On the models that leave the mop at the dock before carpet, that is not an issue; on the rest the pad is lifted, by 7 to 21 mm depending on the model.
- No figure is not zero. Roughly four in ten machines we list publish no threshold height at all. Their product pages say "not published" rather than a guess.
What we would buy
For sills above 4 cm, the X60 Pro Ultra Complete and the V70 Ultra Complete are the only machines with a published margin. For sills between 3 and 4 cm, the 42 to 45 mm group is wide enough to choose on other grounds: our Saros 20 against X60 Pro Ultra Complete comparison is exactly that decision. For an ordinary flat with 2 cm sills, almost anything with a full dock will do, and the best value ranking is the place to start. How we score explains where the threshold figure enters the arithmetic.