Slope and Grade Converter
Edit any one field and the other two update. Percent grade is rise divided by run, times 100. Degrees use the arctangent of rise over run.
Common slope conversions
| Percent | Degrees | Ratio |
|---|---|---|
| 1% | 0.57 | 1 in 100 |
| 2% | 1.15 | 1 in 50 |
| 5% | 2.86 | 1 in 20 |
| 8.33% | 4.76 | 1 in 12 |
| 10% | 5.71 | 1 in 10 |
| 25% | 14.04 | 1 in 4 |
| 100% | 45.00 | 1 in 1 |
Worked example
An accessibility style ramp at 1 in 12: the grade is 1 divided by 12, times 100 = 8.33 percent. The angle is arctan(1/12) = 4.76 degrees. Enter 12 in the ratio field to see both values.
Frequently asked questions
Is a 100 percent slope a vertical wall?
No. A 100 percent grade means rise equals run, which is a 45 degree angle. Percent grade can exceed 100; a vertical wall is infinite percent. Degrees are capped below 90, which is why road signs use percent.
What slope should a driveway or drainage run have?
Driveways are commonly kept under about 15 to 20 percent, and drainage swales and sewer runs often target 1 to 2 percent so water flows without eroding. Local codes vary, so treat these as planning figures only.
Results are provided for general reference. Ramp and grading work must be verified against your local building code.