Quick answer
Slope percentage equals rise divided by horizontal run multiplied by 100. The angle is the arctangent of rise divided by run. Use horizontal run, not the sloped surface length.
Step by step
- Measure rise Use vertical change in inches, feet or millimeters.
- Measure horizontal run Keep it separate from the diagonal length.
- Calculate grade Divide rise by run and multiply by 100.
- Convert angle Use arctan(rise ÷ run) when an angle is needed.
Formula or rule of thumb
Example
A 6 in rise over 10 ft horizontal run is 0.5 ÷ 10 × 100 = 5% grade.
Common mistakes
Using diagonal length as run, confusing a 5% grade with a 5-degree angle, and applying a generic accessibility rule without checking local requirements.
Planning note: product yields, installation methods, site conditions and local requirements can change the final quantity. Use the exact manufacturer or supplier information before purchasing.
Decision guide
| Decision point | What the estimate tells you | What to verify |
|---|---|---|
| Measurements | Start with accurate project dimensions and the correct units. | Replace generic assumptions with site measurements. |
| Product data | Use the actual package yield, coverage or density. | Check the current manufacturer or supplier label. |
| Final decision | Treat the result as an early planning estimate. | Confirm final quantities and requirements before purchase. |
Authority and verification
RenoMetric provides transparent planning arithmetic, not a structural design or contractor quote. Verify final decisions with the current product label or supplier data, the applicable local requirements, and a qualified professional when the project is safety-critical.
- RenoMetric methodology — formulas, units and planning limitations.
FAQ
Is percent grade the same as degrees?
No. They describe the same slope in different ways.
Can this size a ramp?
It can convert dimensions, but ramp design must follow applicable accessibility and safety requirements.
What about drainage?
Drainage slope depends on surface, flow, soil and local design practice.