How Long a Wheelchair Ramp for 3 steps?

Three steps with 7 inch risers are a 21 inch rise, which needs a 21 ft wheelchair ramp at the 1:12 maximum slope, or 26 ft with the 5 ft top landing. Step heights differ from house to house (the chart below runs from 6 to 7.75 inches), so measure the total height from the ground to the door: the ramp needs 1 foot for every inch.

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Example job shown. Change the numbers to match yours.

Ramp length (horizontal run)

21.0 ft

1 inch of rise needs 12 inches of ramp. Measure this along the ground, not along the sloping surface

What to buy

Decking, with 10% extra149 lineal ft of boards, rounded up
Joists per run (16 in centers)4 joists
Joist lumber (size from a span table), with 10% extra93 lineal ft of lumber, rounded up
80 lb bags of concrete mix for those landings (0.6 ft³ each)16 bags

Walking surface length (along the slope): 21.1 ft
Separate ramp runsEach run climbs no more than 30 in: 1 run
Intermediate landings (5 × 5 ft): 0 landings
Landings in total (5 ft × 5 ft clear space at each)1 top + 0 intermediate + 1 clear space at the bottom. The concrete and bag counts below cover the top and intermediate landing (1), not the bottom one: 2 landings
Total footprint with a 5 ft top landing: 26.0 ft
Footprint with the 5 ft clear space at the bottom as wellThe bottom 5 ft is level ground or a landing you pour or lay separately: it is not in the concrete below: 31.0 ft

Materials (wood ramp runs, concrete landings)

Deck boards (5/4×6, laid across the ramp)Each row is one board 3.0 ft long: 45 board rows
Concrete for the top landing (1 at 5 ft × 5.0 ft, 4 in thick, +10%): 9.2 ft³
Same concrete in cubic yards: 0.34 yd³

Requirements to check

Handrails needed (rise over 6 in): Yes, both sides
Handrail length, both sides, with 12 in extensionsEach side: the walking surface length plus 12 in at the top and bottom of every run (ADA Standards 405.8 and 505.10.1). Rail stock, posts and brackets are extra: 47 lineal ft
Clear width: 36 in

Size the joists for their span from a span table or your plans examiner.
Under the ADA, the maximum slope is 1:12, the maximum rise of one run is 30 inches, landings must be at least 60 inches long and as wide as the ramp, and the clear width must be at least 36 inches. Residential rules differ by place, so check local codes, and allow 5 ft of clear space at the bottom. The materials list is a planning estimate for a wood-framed ramp with a concrete top landing and any intermediate landings: the concrete covers the top and intermediate landings only, not the level 5 ft at the bottom. It leaves out posts, footings and guards (the handrail length is given above), whose spacing and size depend on your loads, frost depth and local code.

Before you buy: round up to whole packs, check the size printed on the label, and add a little spare. Your supplier has the final say.

Blueprint

21 ft ramp

Three steps: a typical front porch

Three 7 inch risers put the porch 21 inches above the ground. The ramp is 21 ft at 1:12 and still a single run, because 21 inches is under the 30 inch limit for one run.

The footprint with the top landing is 26 ft, against 1.67 ft for the steps. If the yard is shorter than that, turn the ramp at a landing: each landing is at least 60 inches long, so one turn adds 5 ft of platform and lets the two halves run in different directions.

Ramp length for 3 steps by riser height

Steps are not all the same height, so find your riser in the first column or measure the total rise.

Riser height	Total rise	1:12 ramp	1:16 ramp	1:20 ramp	Runs	Footprint at 1:12
6 in	18 in	18 ft	24 ft	30 ft	1	23 ft
6.5 in	19.5 in	19.5 ft	26 ft	32.5 ft	1	24.5 ft
7 in	21 in	21 ft	28 ft	35 ft	1	26 ft
7.25 in	21.75 in	21.75 ft	29 ft	36.25 ft	1	26.75 ft
7.5 in	22.5 in	22.5 ft	30 ft	37.5 ft	1	27.5 ft
7.75 in	23.25 in	23.25 ft	31 ft	38.75 ft	1	28.25 ft

21 inch rise at each slope

Slope	Ramp length (run)	Along the surface	Percent	Angle	Runs	Footprint with landings
1:12 (ADA maximum)	21 ft	21.07 ft	8.3%	4.8°	1	26 ft
1:16	28 ft	28.05 ft	6.3%	3.6°	1	33 ft
1:20	35 ft	35.04 ft	5.0%	2.9°	1	40 ft

Is a shorter ramp too steep?

Ramp length	Slope	Percent	Angle	Within 1:12?
17 ft	1:9.7	10.3%	5.9°	No, 4 ft too short
19 ft	1:10.9	9.2%	5.3°	No, 2 ft too short
21 ft	1:12	8.3%	4.8°	Yes
25 ft	1:14.3	7.0%	4.0°	Yes

Other step counts (7 inch risers)

Steps	Rise	1:12 ramp	Runs	Footprint
1 step	7 in	7 ft	1	12 ft
2 steps	14 in	14 ft	1	19 ft
4 steps	28 in	28 ft	1	33 ft
5 steps	35 in	35 ft	2	45 ft

Know the height in inches? See a ramp for 20 inches of rise, or the ramp length and slope guide. The stair calculator works out riser heights from a total rise.

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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Portable folding ramp

Frequently asked questions

How long of a ramp do I need for 3 steps?

Measure the total height. 3 steps with 7 inch risers are 21 inches, which needs a 21 ft ramp at 1:12 (1 foot of ramp per inch of rise). With 7.75 inch risers the rise is 23.25 inches and the ramp is 23.25 ft.

Do 3 steps need a ramp with a landing in the middle?

Not for the height. With 7 inch risers the rise is 21 inches, under the 30 inches one run may climb, so the ramp can be one 21 ft run. A middle landing is only needed if the ramp turns.

How high are 3 steps?

Usually 18 to 23.25 inches, at 6 to 7.75 inches a riser. Count every riser, including the last one up onto the porch or threshold, or simply measure from the ground to the door sill.

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.

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