Calculate sidewalk slope, required run, or maximum rise from rise and run measurements and compare results with accessibility limits.
- All Construction Calculators
- All Slope Calculators
- Deck Slope Calculator
- Cross Slope Calculator
- Land Slope Calculator
Sidewalk Slope Formula
The calculator runs three modes. Each uses the same rise-run relationship rearranged for the unknown.
Slope (%) = (Rise / Run) × 100
Run = Rise / (Grade / 100)
Rise = Run × (Grade / 100)
- Rise: vertical change between the two ends of the walk
- Run: horizontal distance, not the sloped surface length
- Grade: slope expressed as a percent
- Angle: arctan(Rise / Run), reported in degrees
Rise and run must use the same unit before dividing. The calculator converts inches, feet, yards, centimeters, and meters to a common base internally. Use the horizontal run, not a tape pulled along the slope, or the grade reads low.
Sidewalk Slope References
Common slope limits used for pedestrian walking surfaces:
| Surface | Max grade | Ratio | Drop per 10 ft |
|---|---|---|---|
| Running slope, accessible walk | 5% | 1:20 | 6 in |
| Cross slope (drainage) | 2% | 1:50 | 2.4 in |
| Ramp segment | 8.33% | 1:12 | 10 in |
| Curb ramp flares | 10% | 1:10 | 12 in |
Quick conversion between percent grade, ratio, and angle:
| Grade | Ratio | Angle |
|---|---|---|
| 1% | 1:100 | 0.57° |
| 2% | 1:50 | 1.15° |
| 5% | 1:20 | 2.86° |
| 8.33% | 1:12 | 4.76° |
| 10% | 1:10 | 5.71° |
Worked Example and FAQ
Example. A 24 ft walkway drops 10 in across its length. Slope = (10 / 288) × 100 = 3.47%. That is under the 5% accessible walking limit. Cross slope of the same walk should still be checked separately at 2% max.
What is the difference between running slope and cross slope? Running slope follows the direction of travel. Cross slope runs perpendicular to it and sheds water. Both have separate limits and must be checked independently.
Do I use the sloped surface length or the horizontal distance? Use the horizontal run. For shallow sidewalk grades the difference is small, but the formula is defined that way and code references follow the same convention.
What if my walk exceeds 5%? Once running slope passes 5%, the path is treated as a ramp. Ramp rules add maximum rise per run, landings, and handrail requirements. Either lengthen the run or break the elevation change into ramp segments with landings.
Why does a flat sidewalk still need some slope? A 1% to 2% cross slope keeps water from ponding. Zero slope causes drainage problems and ice in cold climates.
