What does a 10, 15 or 20 degree slope look like?
A 10° slope rises about 1.76 m over 10 m of horizontal distance, equivalent to 17.6% grade. A 15° slope rises about 2.68 m over the same horizontal distance, equivalent to 26.8% grade. A 20° slope rises about 3.64 m over 10 m horizontally, equivalent to 36.4% grade. These are geometric examples, not mower operating approvals. A photograph can make either bank look flatter or steeper because of the camera position.
Degrees to percent grade: useful reference values
| Angle | Percent grade | Rise over 10 m horizontal | Rise over 1 m horizontal |
|---|---|---|---|
| 5° | 8.7% | 0.87 m | 0.09 m |
| 7° | 12.3% | 1.23 m | 0.12 m |
| 10° | 17.6% | 1.76 m | 0.18 m |
| 15° | 26.8% | 2.68 m | 0.27 m |
| 20° | 36.4% | 3.64 m | 0.36 m |
| 30° | 57.7% | 5.77 m | 0.58 m |
| 45° | 100.0% | 10.00 m | 1.00 m |
Formula: percent grade = tan(angle in degrees) × 100. To work the other way, angle = arctan(percent grade ÷ 100). In particular, 15% grade is about 8.5°, not 15°. A 30° slope is about 57.7% grade.
How to record a slope for a mower inquiry
With rise and run measurements, use the vertical height difference and the horizontal distance between points. Alternatively, use a suitable angle-measuring tool on a representative straight surface and follow its instructions. Do not walk into hazardous terrain to take a measurement. Mark several sections on a site sketch, including turns and ditch edges, and record the steepest measurement separately from the typical one.
Send the unit, measurement method, surface condition and photos together. For a roadside project, continue with the roadside mower selection guide. Compare published specifications in the Tank Series and heavy-duty tracked range after documenting the site.
Degrees and percent grade are different units.
Degree ratings measure the angle between a slope and horizontal ground. Percent grade describes the vertical rise divided by the horizontal distance, multiplied by 100. A 45° angle equals 100% grade; 60° is about 173% grade. Do not compare a percentage on one listing with degrees on another as if they were the same number.
Measure the steepest working section separately from the average site slope. A short ditch edge can be steeper than the surrounding field. Record whether the route climbs straight, crosses sideways or turns on the slope, because those are different operating situations.
A catalog maximum is not a site-wide promise.
For example, the published specifications on this site list the H-550L-A at 45°, the H-800L-D at 60°, and the H-1200L Tank at 70°. These are catalog ratings for named models. They do not establish suitability for every soil condition, direction of travel, attachment or operator procedure.
Ask for the current manual and specification sheet for the exact machine and configuration being quoted. If the slope is near a published limit, request a demonstration or written operating guidance for the comparable terrain before ordering.
Traction and obstacles change the decision.
Describe wet grass, loose soil, ruts, stones, roots and ground that drops away at the edge. Check access for the full machine width, space to turn, obstacles above the machine and a safe place for the operator to stand. A remote control range figure describes the equipment; it is not permission to operate without visibility or beyond local safety rules.
Compare compact tracked, heavy-duty tracked and Tank Series models only after these site details are clear.
Send evidence, not just an angle.
- Steepest measured angle or rise and horizontal run; identify which unit you used.
- Surface conditions in dry and wet weather, plus vegetation and obstacles.
- Available access width, working area, desired cutting width and destination country.
- Photos or a short site video showing the steepest section and turn points.
Have a measured site?
Choose a model or ask us to recommend one. Include your terrain description in the quick quote form; we can discuss the exact configuration and documents before pricing.