Ramp Slope Calculator
Ramp length, slope ratio and landings for ADA compliance.
Enter your values
Enter the total rise in in.
Choose one of: 1:12 ADA public, 1:10 occupied home use, 1:8 unoccupied / loading, 1:20 no handrail needed.
Enter the ramp width in in.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Ramp run needed
- 24 ft (288 in)
- Actual ramp length
- 24.08 ft along the slope
- Slope
- 8.33% (1:12)
- Angle
- 4.8 degrees
- Intermediate landings
- 0 x 60 in
- Total footprint
- 24 ft x 3 ft
Working
- 124 in rise x 12 = 288 in of run
Quick answer
ADA requires a maximum 1:12 slope, so every inch of rise needs 12 inches of ramp, with a level landing every 30 inches of rise.
length = rise x slope ratio; angle = atan(rise / run)
At a glance
| What it does | Ramp length, slope ratio and landings for ADA compliance. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Total rise, Slope ratio, Ramp width |
| Main output | Ramp run needed |
| Formula | length = rise x slope ratio; angle = atan(rise / run) |
| Cost | Free — no sign-up, no download |
How to use the Ramp Slope Calculator
- 1Measure the total vertical rise from the ground to the landing surface.
- 2Choose 1:12 for anything public or wheelchair related.
- 3Add a 5 ft level landing at the top, bottom and every 30 inches of rise.
Inputs explained
- Total rise(in)
- Enter the total rise in in.
- Slope ratio
- Choose one of: 1:12 ADA public, 1:10 occupied home use, 1:8 unoccupied / loading, 1:20 no handrail needed.
- Ramp width(in)
- Enter the ramp width in in.
Worked example
Using the values the calculator loads with:
Inputs
- Total rise24 in
- Slope ratio1:12 ADA public
- Ramp width36 in
Results
- Ramp run needed24 ft (288 in)
- Actual ramp length24.08 ft along the slope
- Slope8.33% (1:12)
- Angle4.8 degrees
- Intermediate landings0 x 60 in
- Total footprint24 ft x 3 ft
- 24 in rise x 12 = 288 in of run
Frequently asked questions
What is the ADA maximum slope?
1:12, or 8.33%. Steeper ramps are only allowed in limited existing-building situations.
How wide must a wheelchair ramp be?
36 inches clear between handrails is the ADA minimum; 42 to 48 inches is far more comfortable to use.
What do I need to enter into the Ramp Slope Calculator?
Just 3 values: total rise, slope ratio, ramp width. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Ramp Slope Calculator work out the answer?
ADA requires a maximum 1:12 slope, so every inch of rise needs 12 inches of ramp, with a level landing every 30 inches of rise. It applies the formula length = rise x slope ratio; angle = atan(rise / run) and shows the working so you can check each step by hand.
Is the Ramp Slope Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.