Numbers, Units & Calculators
ADA Wheelchair Ramp Slope Calculator
Plan equal ramp runs, landings, and straight or turning footprints. Check slope, rise, width, handrails, and available length.
Worked example result
Select Load example to use these values in the calculator.
- Rise
- 30
- Unit
- in
- Slope
- 1:12
- Layout
- straight
- Clear width (inches for in/ft; centimetres for cm/m)
- 36
- Available length
- 480
Total horizontal ramp length
- Slope ratio
- 1:12
- Percent grade
- 8.33%
- Angle
- 4.76 degrees
- Number of runs
- 1
- Rise per run
- 30 in (76.2 cm)
- Run length
- 360 in (914.4 cm)
- Landings
- 2
- Footprint
- 480 in (1219.2 cm) long × 36 in (91.4 cm) wide
Segment plan
| Segment | Length | Rise | Direction or note |
|---|---|---|---|
| Bottom landing | 60 in (152.4 cm) | 0 in (0 cm) | Width 36 in (91.4 cm) |
| Run 1 | 360 in (914.4 cm) | 30 in (76.2 cm) | Forward |
| Top landing | 60 in (152.4 cm) | 0 in (0 cm) | Width 36 in (91.4 cm) |
Checks
| Rule | Section | Your value | Limit | Result |
|---|---|---|---|---|
| Running slope | 405.2 | 1:12; rise 30 in (76.2 cm) | 1:12 maximum | Pass |
| Rise per run | 405.6 | 30 in (76.2 cm) | 30 in maximum | Pass |
| Clear width | 405.5 | 36 in (91.4 cm) | 36 in minimum between handrails | Pass |
| Landings | 405.7 | 2; dimensions in Segment plan | 60 in long; run width; turns at least 60 by 60 in | Pass |
| Cross slope | 405.3 | Not measured | 1:48 maximum | Check on site |
| Landing slope | 405.7 | Not measured | 1:48 maximum | Check on site |
| Handrails | 405.8; 505 | Required on both sides | Required above 6 in rise; height 34 to 38 in | Check on site |
| Available length | Planning geometry | 480 in (1219.2 cm) | 480 in (1219.2 cm) | Pass |
This is a planning aid. It is not a compliance determination. Local codes and the authority having jurisdiction decide. ADA scope differs for private homes.
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The planner splits total rise into equal runs and adds landings for the selected layout.
The result includes a segment plan, footprint dimensions, and checks for the entered geometry.
- Homeowners can estimate the space between a porch and a driveway.
Sources: ADA Accessibility Guidelines guide: Ramps and Curb Ramps
Geometry does not establish site compliance
- Available length checks length only, not site width or obstacles.
- Footprints omit walls, rail projections, foundations, and door clearances.
- Alteration slope options require conditions outside this calculator.
- A passing geometry check does not establish ADA compliance.
Enter rise, slope, and landing layout
- Enter Rise and Unit, then choose Slope and Layout.
- Enter Clear width in inches for in/ft, or centimetres for cm/m.
- Optionally enter Available length, then select Plan runs and landings.
Plan runs for a 30-inch rise
Input: Rise: 30 in
Settings: Slope: 1:12; Layout: Straight; Clear width: 36 in
Result: 30 ft 0 in (9.14 m)
One run rises 30 inches across 360 inches. Two landings increase the straight footprint length to 480 inches.