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Robot mower slope ratings, explained
Updated
Slope ratings are given in percent: feet of rise per 100 feet of distance. A 45 percent slope is about 24.2 degrees, not 45. And several makers allow a much gentler slope at the edge of the lawn than inside it, often 10 percent.
Percent to degrees
| Percent | Degrees | What it looks like |
|---|---|---|
| 10% | 5.7 | A gentle grade you barely notice walking |
| 30% | 16.7 | A noticeable bank |
| 35% | 19.3 | Steeper than most front lawns |
| 45% | 24.2 | Hard to push a mower up |
| 50% | 26.6 | A steep hillside |
| 80% | 38.7 | Very steep. Hard to stand on when wet |
| 100% | 45.0 | One foot up for every foot across |
To measure, set a straight board level on the slope, measure the gap under the low end, and divide it by the board length. A 4 ft board with a 16 in gap is 16 / 48 = about 33 percent.
- Mammotion LUBA mini 280 % slope
- ECOVACS GOAT A2000 (maker page)50 % slope
- Husqvarna 410iQ45 % slope
- Gardena SILENO City35 % slope
- Navimow i105N (maker page)30 % slope
- WORX WR32030 % slope
The edge rule
Gardena gives the SILENO City 35 percent inside the lawn but 10 percent at the boundary. Navimow gives the i105 30 percent inside and 10 percent at the boundary. On a slope that runs out to the edge, a mower can slide past the line while turning. If your lawn ends at a slope, a drop or a pond, check the edge figure, not the headline.
What slope does to capacity
Climbing takes more battery and the mower slows down. Near its limit it can lose grip on wet grass and need a second try. In the calculator, gentle slopes cost 10 percent of capacity and slopes near the rating cost 25 percent. Those are our assumptions.
The picks by slope
- Mammotion LUBA mini 2 AWD 1500H. All-wheel drive with two 88W motors and an 80 percent slope claim on the listing. Maker claims it steps over curbs and roots up to 45 mm. The caveat: it weighs 54.9 lb, and some owners report mapping trouble.
- ECOVACS GOAT A2000 LiDAR PRO. ECOVACS's page claims 50 percent (27 degrees). The Amazon listing we read did not state a slope, so check before you count on it.
- Husqvarna Automower 410iQ. 45 percent on the listing. The caveat: owner feedback is mixed on mowing under trees.
- Gardena SILENO City, Segway Navimow i105N and WORX Landroid Vision Cloud WR320. 35, 30 and 30 percent. Fine for gentle yards. Not for hillsides.
Safety on slopes
Keep a steep bank out of the mowing map if the mower struggles on it, and never try to catch a mower sliding down a hill by hand. Stop it from the app or the stop button and let it settle first.
Check your own yard with the capacity calculator, or compare all six picks on the best robot mowers page.