Percent is not degrees
A slope in percent is the height difference per 100 m of horizontal distance: % = 100 · tan(α). So 100 % is 45°, not 90°. A ratio 1 : n means 1 m up for n m horizontally: n = 100 / %.
| Slope | Degrees | Typical |
|---|---|---|
| 1–2 % | 0.6–1.1° | sewer pipes, flat roofs, terraces (drainage) |
| 6–8 % | 3.4–4.6° | wheelchair ramps (limits depend on the regulation) |
| 10–12 % | 5.7–6.8° | steep road |
| 58 % | 30° | avalanche terrain starts around here |
| 100 % | 45° | steep ski slope / couloir |
On a map, the horizontal distance is what you measure; on the ground you walk the slightly longer slope length √(height² + distance²). For walking times see the Hiking Time Calculator.