Robot Mowers on Hills: Slope Ratings Explained
How slope ratings work, percent vs degrees, the boundary rule most buyers miss, every rating we track and how to measure your own yard.
By , research by the BestBots team · Updated Oct 19, 2026
Fact checked against each company's published pricing, documentation and verified user ratings. How we score
Yes, robot mowers can handle hills, within their slope rating. The steepest we track are the Segway Navimow X4 and Worx Landroid Vision 4WD at 84% (40 degrees), then the Mammotion Luba 3 AWD at 80%. Most two wheel drive models stop at 45% to 50%, and many brands rate the lawn's edge lower than its middle.
Segway Navimow X44.3
Mammotion Luba 3 AWD4.2
Husqvarna Automower 435 iQ AWD4.1Percent vs degrees
Brands quote slope two ways. Percent is rise over run; degrees is the angle. They are not the same number.
| Percent | Degrees | What it feels like |
|---|---|---|
| 15% | 8.5° | A gentle grade |
| 32% | 18° | A noticeable lawn slope |
| 45% | 24° | Steep to walk with a push mower |
| 50% | 27° | Very steep lawn |
| 70% | 35° | Hard to stand on when wet |
| 80% | 39° | Near the limit for any mower |
| 84% | 40° | The steepest robot rating we track |
| 100% | 45° |
Every slope rating we track
| Mower | Max slope | Drive | Lawn area |
|---|---|---|---|
| Segway Navimow X4 | 84% (40°); crosses 2.8 in obstacles | AWD | 1.0 or 1.5 acres |
| Worx Landroid Vision Cloud 4WD | 84% (40°) | 4WD | 1/4 to 1 1/2 acres |
| Mammotion Luba 3 AWD | 80% (38.6°) | AWD | 0.37 to 1.25 acres |
| Mova LiDAX Ultra 3000 AWD | 80% per its Amazon listing title | AWD | 0.75 acre |
| Husqvarna Automower 435 iQ AWD | 70% inside, 50% at boundary | AWD | 1.3 acres |
| Husqvarna Automower 435X AWD | 70% inside, 50% at boundary | AWD | 0.9 acre |
| Yarbo Y40 Lawn Mower Pro | 70% (35°) | Not listed here | Up to 6 acres |
| Ecovacs Goat A3000 LiDAR Pro | 50% (27°) | Not listed here | 0.74 acre |
| Segway Navimow i2 LiDAR | 45% (24°) with off road wheels | Not listed here | 0.37 acre |
| Mammotion YUKA mini 2 1000H | 45% (24°) | Not listed here | 0.25 acre |
| Husqvarna Automower 440 iQ | 45% inside, 15% at boundary | Not listed here | 2 acres |
| eufy E15 | 18° (about 32%) | Not listed here | 0.2 acre |
Ratings are the brands' own. Wet grass, loose soil and turning on a slope all reduce real grip.
The boundary rule
Husqvarna is the only brand we track that publishes two numbers: the steepest slope inside the lawn and the steepest slope at the boundary. On the 435 iQ AWD that is 70% inside and 50% at the edge; on the 440 iQ, 45% inside and only 15% at the edge. The edge number is lower because the robot turns there and must not slide past the boundary. If your steep section runs right up to a fence, a drop or a pond, use the boundary figure and leave margin.
What makes a mower good on hills
- All wheel drive. Most ratings above 50% here come from AWD or 4WD models.
- Wheels and tires. Navimow rates the i2 LiDAR at 45% with off road wheels.
- Obstacle crossing. Hills come with roots and edges; the Navimow X4 crosses obstacles up to 2.8 in.
- Navigation that holds position. Slopes often sit under trees. LiDAR and RTK plus vision (Luba 3, Navimow X4) keep track when satellite signal is weak.
- Runtime. Climbing drains batteries. The Luba 3 lists up to 215 minutes per charge.
How to measure your slope
- Find the steepest section, including near edges.
- Lay a straight board, say 4 ft, downhill with one end on the ground.
- Raise the low end until a level on the board reads level.
- Measure the gap from the low end to the ground.
- Gap divided by board length, times 100, is the slope in percent. A 2 ft gap on a 4 ft board is 50%.
Compare that to the inside and boundary ratings, and buy a mower with at least 10 points of headroom over your steepest spot.
Our picks for hills
- Steepest yards: Segway Navimow X4, 84% and 2.8 in obstacle crossing.
- Steep and shaded: Mammotion Luba 3 AWD, 80% with LiDAR, RTK and vision.
- Steep and small: Worx Landroid Vision WR341, 84% on a 1/4 acre model. See Best Robot Lawn Mowers for Small Yards.
- Dealer support: Husqvarna Automower 435 iQ AWD, 70% inside the lawn.
Consumer Reports notes that flat, rectangular yards are the easiest for robots; slopes, rocks and trees make the job harder. A robot can mow a steep lawn, but expect more setup time and an occasional rescue in wet weather. Full rankings: Best Robot Lawn Mowers.
Frequently asked questions
Can robot mowers handle hills?
Yes, within their rating. All wheel drive models now list 70% to 84% slopes: the Navimow X4 and Worx Landroid Vision 4WD at 84% (40 degrees), the Mammotion Luba 3 at 80% and the Husqvarna 435 iQ AWD at 70%. Two wheel drive models usually stop at 45% to 50%.
What is the best robot mower for steep hills?
The Segway Navimow X4 (84%, 40 degrees, crosses 2.8 in obstacles) for most steep yards, the Mammotion Luba 3 AWD (80%) if trees block the sky, and the Husqvarna 435 iQ AWD (70%) if you want a dealer network.
Is a 45 percent slope the same as 45 degrees?
No. Percent is rise over run: 45% means 45 ft up for every 100 ft across, about 24 degrees. 100% is 45 degrees. Brands mix the two, so convert before comparing.
What does the boundary slope rating mean?
It is the steepest slope allowed along the edge of the mowing area, where a robot turns. Husqvarna lists 70% inside the lawn but 50% at the boundary on the 435 iQ AWD, and 45% inside but 15% at the boundary on the 440 iQ. Steep edges next to drops need extra margin.
Do I need an AWD robot mower for my hill?
If any part of your lawn is steeper than about 45% (24 degrees), yes. AWD and 4WD models from Husqvarna, Mammotion, Segway, Mova and Worx carry the 70% to 84% ratings.
How do I measure the slope of my yard?
Lay a straight board on the slope, level it with a bubble level, and measure the gap from the board's low end to the ground. Gap divided by board length, times 100, is the slope in percent. Many phone level apps also read degrees.