Eight inches: where handrails start
An 8 inch rise is one tall step, or a low step with a raised door sill on top. It is over the 6 inch line, so unlike a 6 inch ramp this one needs handrails on both sides: 21 lineal feet of rail in all, because each side follows the 8.03 ft of sloping surface and then runs 12 inches level at the top and at the bottom.
The ramp itself is short, but the level space around it is not. A 5 ft landing at the door and 5 ft clear at the bottom make 10 ft of level space against 8 ft of slope, so the whole route is 18 ft from the house.
8 inch rise at each slope
| Slope | Ramp length (run) | Along the surface | Percent | Angle | Runs | Footprint with landings |
|---|---|---|---|---|---|---|
| 1:12 (ADA maximum) | 8 ft | 8.03 ft | 8.3% | 4.8° | 1 | 13 ft |
| 1:16 | 10.67 ft | 10.69 ft | 6.2% | 3.6° | 1 | 15.67 ft |
| 1:20 | 13.33 ft | 13.35 ft | 5.0% | 2.9° | 1 | 18.33 ft |
The footprint adds a 5 ft landing at the top. Allow 5 ft of clear, level space at the bottom too: with it the 1:12 ramp needs 18 ft from end to end. That bottom space is not in the concrete estimate below.
Is my ramp too steep for 8 inches?
Slope is rise ÷ run. For an 8 inch rise, a ramp shorter than 8 ft is steeper than 1:12:
| Ramp length | Slope | Percent | Angle | Within 1:12? |
|---|---|---|---|---|
| 4 ft | 1:6 | 16.7% | 9.5° | No, 4 ft too short |
| 6 ft | 1:9 | 11.1% | 6.3° | No, 2 ft too short |
| 8 ft | 1:12 | 8.3% | 4.8° | Yes |
| 12 ft | 1:18 | 5.6% | 3.2° | Yes |
Materials for the 8 ft ramp
A wood ramp 8 ft long and 36 inches wide takes 18 rows of 5/4×6 deck boards laid across it, 60 lineal feet with 10% extra, on 4 joists per run at 16 inch centers (36 lineal feet). The 4 inch concrete for the top landing is 0.34 cubic yards, about 16 bags of 80 lb mix. Built 48 inches wide, the decking rises to 80 lineal feet on the same 4 joists per run. Handrails on both sides, with a 12 inch level extension at the top and bottom of the run, come to 21 lineal feet of rail. Posts, brackets and footings are not in these figures.
Ramp length for nearby rises
| Rise | 1:12 | 1:16 | 1:20 | Runs | Footprint at 1:12 |
|---|---|---|---|---|---|
| 6 in | 6 ft | 8 ft | 10 ft | 1 | 11 ft |
| 8 in | 8 ft | 10.67 ft | 13.33 ft | 1 | 13 ft |
| 10 in | 10 ft | 13.33 ft | 16.67 ft | 1 | 15 ft |
| 12 in | 12 ft | 16 ft | 20 ft | 1 | 17 ft |
Coming down steps instead of a measured height? See a ramp for 1 step or a ramp for 2 steps, or read the ramp length and slope guide.
Want to change anything else? The calculator above is the full Wheelchair Ramp Calculator: edit any number and the results update instantly.
Tools & materials for this project
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Frequently asked questions
How long does a wheelchair ramp need to be for an 8 inch rise?
8 ft at the 1:12 maximum slope, because every inch of rise needs 12 inches of ramp. With the landings it takes up 13 ft. At 1:16 the ramp is 10.67 ft and at 1:20 it is 13.33 ft.
Does an 8 inch rise need handrails on the ramp?
Yes under the ADA figures, on both sides, because the rise is more than 6 inches. With the 12 inch extensions at each end that is 21 lineal feet of rail for the 8 ft ramp. Local residential rules can differ.
What is the slope of an 8 ft ramp with an 8 inch rise?
1:12, which is 8.3% or 4.8 degrees. Divide the rise by the run in the same unit: 8 ÷ 96 inches = 0.0833.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.