Yard Bot Lab
Robot mowers buying guide

Robot mower slope ratings explained: percent, degrees, and the boundary figure

Slope is the spec that eliminates the most robot mowers on a hilly lawn, and it is published in two different units against at least two different places on the lawn. Read the wrong one and you buy a machine rated for ground it will never have to hold. We have not hardware-tested any of these machines. Every figure below is quoted from the manufacturer's own published spec, with the basis its datasheet states.

Figures in this guide come from the manufacturer datasheets behind our model pages, verified 2026-07-30.

What a slope rating states, and what it does not

A published slope rating is a manufacturer claim about a grade the machine is rated to climb, established on the maker's own terms. It is not a promise about wet grass, about traversing a slope diagonally, or about a lawn with a lip at the top of the rise. Across the nine active robot mowers we publish pages for, every maker publishes at least one slope figure, and four of them publish a second, lower figure that applies at the lawn boundary.

Two things vary from datasheet to datasheet: the unit the figure is printed in, percent or degrees or both, and the location the figure applies to, the interior working area or the mapped edge. Some makers also attach a condition, such as the equipment fitted or the fact that the number came from a lab. A rating with none of those qualifiers is still a claim, just a less specific one.

We quote each figure as its datasheet states it. We do not convert a boundary figure into an interior one, do not turn a per-model figure into a per-brand one, and do not fill a gap with an estimate. Where a maker publishes nothing, not published is the finding.

Percent and degrees are the same figure in two units

Most makers print both units, which is why the same mower can look like two different machines depending on which number a listing quotes. Percent is rise over run, so a 100 percent grade is 45 degrees. That is why the steepest mowers in this set, published at 80 percent, land near 38.6 degrees rather than anywhere close to 80 degrees. The practical trap is reading a percent figure as if it were degrees: a mower published at 45 percent is rated for roughly 24 degrees, not 45.

Two makers publish a single unit or attach a condition to the pair. Husqvarna publishes the Automower 420 iQ as maximum slope performance inside installation, 45 percent, with no degree equivalent alongside it. Sunseeker publishes the X7 as 70 percent / 35 degrees climbing capacity and states the figure is achieved with the all wheel drive system and off road tires, which makes the equipment part of the claim rather than a separate note.

The boundary figure is a second, lower rating

Four of the nine active models publish a separate limit for the edge of the lawn, and in every case it sits well below the interior number. Segway publishes the Navimow i110N at 30 percent (17 degrees) maximum slope ability with a 10 percent (6 degrees) maximum slope at the boundary. Segway publishes the Navimow X350 at 50 percent (27 degrees) maximum slope ability with maximum slope performance at the boundary of 25 percent (14 degrees). Husqvarna publishes the Automower 420 iQ at 45 percent inside the installation with slope at the boundary limited to 15 percent. Ecovacs publishes the GOAT O1000 RTK at 45 percent (24 degrees) maximum slope for the work area, with a separate lower limit of 17 percent that applies along virtual boundaries per its US spec table.

Read those four pairs together and the boundary limit lands somewhere between roughly a third and a half of the same mower's interior figure. Makers do not explain the gap on the spec table, but the edge is where the machine has to hold a line and turn rather than simply climb, and on a wire-free mower it is also where the machine is working at the limit of its mapped boundary. The practical consequence is straightforward: if your steep ground runs to the edge of the lawn rather than sitting in the middle of it, the boundary figure is the one that governs the purchase.

The other five active models publish a single slope figure with no separate boundary limit. That silence is not a statement that the headline figure holds at the edge, and we do not read it as one. It is an absence, recorded as not published.

The conditions makers attach to the number

Dreame is the most explicit about where its figure came from. The A3 AWD Pro 3500 max slope performance figure of 80 percent (38.7 degrees) carries a footnote stating that all data is based on in house or third party lab testing and that actual performance may vary. Sunseeker attaches equipment instead of a lab, publishing the X7 figure as achieved with the all wheel drive system and off road tires. Husqvarna attaches a location, publishing the 420 iQ figure as maximum slope performance inside installation. Mammotion publishes the LUBA 3 AWD 3000 figure as max climbing ability with no stated test condition.

Drivetrain is worth reading next to the number rather than inferred from it. Three of the four steepest published figures come with a published all wheel or four wheel drive claim: the LUBA 3 AWD 3000 at 80 percent, the A3 AWD Pro 3500 at 80 percent from what Dreame calls its all terrain 4WD system, and the X7 at 70 percent. Segway, by contrast, publishes the Navimow X350 as rear wheel drive and rates it at 50 percent (27 degrees), which places a rear wheel drive machine above all three of the 45 percent models in this set. Drive layout correlates with the published rating here, but it does not determine it.

One discontinued model shows how far a maker will go in caveating a slope figure. EcoFlow published the Blade at 50 percent (27 degrees) max incline in its official manual, with the manual stating that spec data was measured in a laboratory and is for reference only. EcoFlow has delisted the Blade from its US store, so we cite it here only as documentation of the practice, not as an option to buy.

Matching a rating to your own lawn

Start by establishing the grade you actually have and where it sits, because the same lawn can pass or fail depending on which of the two published figures applies to it. A slope in the middle of a mapped area is measured against the interior rating. A slope that runs to the mapped edge is measured against the boundary rating, where four of the nine models publish a limit between roughly a third and a half of their headline number and the other five publish nothing.

Read conditionally from there. Above roughly 50 percent, the published figures point to the Mammotion LUBA 3 AWD 3000 and the Dreame A3 AWD Pro 3500 at 80 percent, or the Sunseeker X7 at 70 percent, and the LUBA 3 versus A3 AWD Pro and LUBA 3 versus X7 comparisons set those three against each other. In the 45 to 50 percent band sit the Segway Navimow X350, the Husqvarna Automower 420 iQ, the Ecovacs GOAT O1000 RTK, and the Mammotion YUKA mini 2 1000H, with the first three carrying published boundary limits of 25, 15, and 17 percent respectively. At 30 percent, the Segway Navimow i110N and Worx Landroid Vision WR208 are gentle-yard ratings, and the i110N drops to 10 percent at the boundary.

Slope rarely decides a purchase alone. Our guide to steep and large lawns reads the slope figures against published work area, and how to choose a robot mower puts slope in line with the other specs that carry a measurement basis. Whatever the number, treat it as the maker's claim about its own machine on its own test, not as a guarantee about your hill.

Frequently asked questions

What does an 80 percent slope rating mean on a robot mower?
Percent is rise over run, so 80 percent is about 38.6 degrees, not 80 degrees. Two models we publish pages for carry that rating: Mammotion publishes the LUBA 3 AWD 3000 at 80 percent (38.6 degrees) max climbing ability, and Dreame publishes the A3 AWD Pro 3500 at 80 percent (38.7 degrees) max slope performance with a footnote stating the data is from in house or third party lab testing. Both are manufacturer claims; we have not hardware-tested either machine.
Is a robot mower slope rating in percent the same as a rating in degrees?
They are the same figure in two units, and most makers print both. Segway publishes the Navimow i110N at 30 percent (17 degrees), Ecovacs publishes the GOAT O1000 RTK at 45 percent (24 degrees), and Segway publishes the Navimow X350 at 50 percent (27 degrees). Husqvarna publishes the Automower 420 iQ in percent only, at 45 percent, with no degree equivalent on the spec page.
Why is the boundary slope rating lower than the main slope rating?
Makers publish a separate, lower limit for the mapped edge of the lawn, where the machine has to hold a line and turn rather than simply climb. Among the models we publish pages for, the Segway Navimow X350 drops from 50 percent to 25 percent at the boundary, the Husqvarna Automower 420 iQ from 45 percent to 15 percent, the Ecovacs GOAT O1000 RTK from 45 percent to 17 percent along virtual boundaries, and the Segway Navimow i110N from 30 percent to 10 percent.
Does every robot mower publish a boundary slope figure?
No. Four of the nine active models we publish pages for do: the Segway Navimow i110N, the Segway Navimow X350, the Husqvarna Automower 420 iQ, and the Ecovacs GOAT O1000 RTK. The Mammotion LUBA 3 AWD 3000, Dreame A3 AWD Pro 3500, Sunseeker X7, Mammotion YUKA mini 2 1000H, and Worx Landroid Vision WR208 publish a single slope figure with no separate boundary limit. We record that as not published rather than assume the headline figure applies at the edge.