Wheelchair Ramp Calculator
Find how long a wheelchair ramp needs to be. Enter the total rise and choose a slope to get the run length, the number of ramp runs and landings, the angle and grade, and handrail notes based on the 2010 ADA Standards.
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Vertical height from the lower level to the top surface
Run per 1 unit of rise
36 in (91.5 cm) minimum between handrails
How to use the Wheelchair Ramp Calculator
- Measure the total rise from the ground (or lower floor) to the top of the threshold or landing.
- Choose a slope: 1:12 is the ADA maximum; 1:16 or 1:20 is easier to push.
- Enter the clear width between handrails (36 in minimum).
- Press Calculate to see the run length, landings and handrail notes.
- Compare slopes in the table to see how much space a gentler ramp needs.
Ramp length formulas
- Run length = total rise × slope ratio (1:12 → rise × 12)
- Number of runs = ⌈total rise ÷ 30 in⌉; intermediate landings = runs − 1
- Total length = run length + (intermediate landings + 2) × 60 in
- Angle = arctan(1 ÷ ratio); grade = 100 ÷ ratio %
Worked example: a 42 in porch at 1:12. Run = 42 × 12 = 504 in = 42 ft. 42 ÷ 30 = 1.4, so 2 runs of 21 in rise (21 ft each) with 1 intermediate landing. With 5 ft landings at the top, middle and bottom, the ramp takes 42 + 15 = 57 ft of length if built straight. The rise is over 6 in, so handrails are needed on both sides.
Ramp length by rise
| Rise | Run at 1:12 | Run at 1:16 | Run at 1:20 | Mid landings (1:12) |
|---|---|---|---|---|
| 6 in | 6 ft | 8 ft | 10 ft | 0 |
| 12 in | 12 ft | 16 ft | 20 ft | 0 |
| 18 in | 18 ft | 24 ft | 30 ft | 0 |
| 24 in | 24 ft | 32 ft | 40 ft | 0 |
| 30 in | 30 ft | 40 ft | 50 ft | 0 |
| 36 in | 36 ft | 48 ft | 60 ft | 1 |
| 48 in | 48 ft | 64 ft | 80 ft | 1 |
| 60 in | 60 ft | 80 ft | 100 ft | 1 |
Key ADA ramp requirements (2010 Standards)
| Item | Requirement | Section |
|---|---|---|
| Running slope | 1:12 maximum | 405.2 |
| Cross slope | 1:48 maximum | 405.3 |
| Clear width | 36 in (915 mm) minimum | 405.5 |
| Rise per run | 30 in (760 mm) maximum | 405.6 |
| Landing length | 60 in (1525 mm) minimum; 60 × 60 in at turns | 405.7 |
| Handrails | Both sides when rise > 6 in; 34–38 in high | 405.8, 505 |
| Edge protection | Curb or barrier on drop-offs | 405.9 |
This is a planning aid, not legal advice. Local codes may be stricter; confirm requirements with your building department before you build.
Frequently asked questions
How long does a wheelchair ramp need to be?
Multiply the rise by the slope ratio. At the ADA maximum slope of 1:12, every inch of rise needs 12 inches of ramp, so a 24 in rise needs a 24 ft run, plus a 5 ft landing at the top and bottom. A gentler 1:16 slope needs 32 ft for the same rise.
What is the ADA ramp slope requirement?
Under the 2010 ADA Standards for Accessible Design (section 405.2), a ramp's running slope must be 1:12 (8.33%, about 4.8°) or less. Cross slope must not exceed 1:48. In existing buildings where space is limited, steeper slopes are allowed only for short rises: up to 1:10 for a rise of 6 in or less, and up to 1:8 for a rise of 3 in or less.
When does a ramp need a landing?
ADA section 405.6 limits each ramp run to a rise of 30 in (760 mm). Every run needs a level landing at the top and bottom that is at least 60 in (1525 mm) long and at least as wide as the ramp. Where a ramp changes direction, the landing must be at least 60 × 60 in.
When are handrails required on a ramp?
Ramp runs with a rise greater than 6 in (150 mm) need handrails on both sides (ADA 405.8). The top of the gripping surface goes 34 to 38 in (865–965 mm) above the ramp surface, and the rails extend at least 12 in (305 mm) horizontally beyond the top and bottom of each run unless they continue around a switchback.
How wide should a wheelchair ramp be?
The ADA requires a clear width of at least 36 in (915 mm) measured between handrails. Wider ramps, 42 to 48 in, are more comfortable and give room for a helper walking beside the user.
What angle is a 1:12 ramp?
A 1:12 slope is arctan(1/12) ≈ 4.76°, an 8.33% grade. A 1:16 slope is about 3.58° (6.25%), 1:20 is about 2.86° (5%), and 1:8 is about 7.13° (12.5%).
Do home wheelchair ramps have to follow ADA rules?
The ADA Standards apply to public accommodations and commercial facilities, not to most private homes. Many local building codes, accessibility programs and grant programs still use 1:12 or gentler for home ramps, so check with your local building department before building.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.