Robot mower slope guide: percent, degrees and how to measure
Slope ratings decide which robot can climb your lawn. Here's how to read them and measure your own slope with a phone.
Percent vs degrees
A slope percentage is rise ÷ run × 100. A 100% slope rises one metre for every metre across, which is 45°. Percent grows faster than degrees, so manufacturers often quote the bigger-sounding percentage.
| Degrees | Percent | What it means here |
|---|---|---|
| 10° | 18% | Gentle lawn, any mower here |
| 17° | 31% | eufy E15 and Navimow i105 limit area |
| 24.2° | 45% | Navimow i2 series and Husqvarna 410/420/440 iQ limit |
| 27° | 51% | Navimow X3 limit |
| 35° | 70% | Husqvarna 435 iQ AWD limit |
| 38.6° | 80% | Mammotion LUBA and Dreame A3 limit |
| 40° | 84% | Navimow X4 and WORX Vision 4WD limit |
Measuring your slope
- Phone level app. Lay a straight board on the steepest part of the lawn, place the phone on it and read the angle in degrees.
- Rise over run. Hold a 1 m (or 3 ft) level horizontally from the high point and measure the gap down to the grass at the other end. Gap ÷ length × 100 = percent.
Use the steepest section
A mower must handle the steepest part it crosses, including the edges. Some makers rate lower at the boundary than inside the lawn, and wet grass reduces grip. Leave a margin of 5–10 percentage points.
See every climber in best robot mowers for hills.