Ramp Size Calculator
Enter the height from the ground to the top of the step or door threshold, and choose the slope. The calculator gives the ramp run, the angle, how many landings you need and the total length.
- Ramp length
- Landings
- Angle
Measure the rise from the ground where the ramp will start.
At the ADA maximum of 1:12, each inch of rise needs 12 in of ramp. A 24 in rise at 1:12 needs a 24 ft ramp. It is under 30 in of rise, so it can be one run with a landing at the top and bottom.
Ramp length chart
For each rise and slope. Search for a rise.
| Rise | 1:8 | 1:12 | 1:16 | 1:20 |
|---|---|---|---|---|
| 3 in | 2 | 3 | 4 | 5 |
| 6 in | 4 | 6 | 8 | 10 |
| 12 in | 8 | 12 | 16 | 20 |
| 18 in | 12 | 18 | 24 | 30 |
| 24 in | 16 | 24 | 32 | 40 |
| 30 in | 20 | 30 | 40 | 50 |
| 36 in | 24 | 36 | 48 | 60 |
| 48 in | 32 | 48 | 64 | 80 |
Feet.
Rise and ramp length
At 1:12. Slide the rise.
The ramp is drawn from the side.
How to size a ramp
Rise to ramp. Step through it.
Rise
Measure ground to top.
Add handrails both sides when the rise is over 6 in.
1:8, 1:12 or 1:20
Ramp slopes. Compare them.
Steep.
ADA.
Gentle.
Gentler slopes help people who push their own chair.
Before you build
Ramp checks. Tick each item.
Tick each item as you go.
Make the surface slip resistant in wet weather.
What you get
Ramp sizing. Each tile explains one result.
Run.
Degrees.
Count.
With landings.
Clear.
A ramp that is too steep is hard to climb and dangerous to come down.
Frequently Asked Questions
No question matches that search.
How long should a wheelchair ramp be?
One foot of ramp for every inch of rise at the ADA slope.
What is the maximum ramp slope?
One in twelve under the ADA for most ramps.
When does a ramp need a landing?
At least every thirty inches of rise, plus at the top and bottom.
How wide should a ramp be?
At least thirty six inches clear between handrails.
Can a ramp be steeper for a scooter?
Short assisted ramps can be one in eight, but not for public use.
Do ramps need handrails?
Yes under the ADA when the rise is over six inches.
Easy access
Size the ramp to the rise and getting in and out is easy and safe.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.