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Can a robot mower handle your hill?

Slope rating is the spec buyers ignore until the mower slides downhill. Manufacturers rate max slope as percent grade — a 45% grade is about 24°, much steeper than it sounds. Set your steepest hill below.

Tip: measure rise over a 10-ft run — 3 ft of rise = 30% grade.

Percent grade vs. degreesMower specs use percent grade (rise ÷ run × 100). It sounds steeper than degrees: 100% is only 45°.
Run: 10 ft Rise: 3 ft 30% grade ≈ 17°

How to measure: lay a 10-ft board on the slope, level it, and measure the gap at the low end.

15% · 9° 30% · 17° 45% · 24° 60% · 31° 80% · 39° 100% · 45°

Common ratings. Highlighted: 45% (typical 2WD ceiling) and 80% (AWD flagships).

What the grades mean

Percent gradeDegreesWhat it feels like
15%~8.5°Gentle — every mower handles this
30%~16.7°Noticeable hill — check mid-range models
45%~24°Steep — most standard mowers max out here
60%~31°Very steep: AWD models only
80%+~39°+Extreme: top AWD flagships or tracked mowers
Rated maximum slope by modelPercent grade, manufacturer ratings on dry grass. 45% ≈ 24°, 80% ≈ 39°.

Wet grass and side-slopes cut real-world ability, so leave a 10–15% margin. Check your hill with the slope checker.

A note on real-world slopes

Manufacturer ratings assume dry grass and good traction. Wet slopes, loose soil, and side-hill mowing all reduce real capability — we build a 12% safety margin into the results above. All-wheel-drive models like the Mammotion LUBA 3 AWD, Segway Navimow X4 and Dreame A3 AWD genuinely outperform two-wheel mowers on hills. That's not just marketing.

Next: match a mower to your full lawn or read our slope limits guide.