Ramp Calculator
Work out the length, slope and landings a wheelchair or loading ramp needs from the rise, with the ADA 1:12 limit checked for you. Enter the rise in feet and inches; add the length of a ramp the client already has to see whether it passes.
Your numbers
From the ground where the ramp starts to the top of the threshold or deck. Decimals: 6.5 for 6-1/2.
Optional: the horizontal length of an existing or quoted ramp, to check it against 1:12.
Horizontal length needed
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- Slope
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- Length along the ramp surface
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- Ramp runs
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The calculation runs in your browser and ParrotNotes does not store your numbers. They sit in the page address so you can bookmark or share the result.
How the ramp length is worked out
A slope of 1:12 means 12 inches of horizontal run for each inch of rise. Measure the rise from the ground where the ramp will start to the top of the threshold or deck, then multiply by the ratio: that is the horizontal length of the ramp, without landings.
The ADA caps each run at a 30 inch rise, so a bigger rise is split into runs with a level landing between them, and every run has a landing at the top and the bottom. Each landing is at least 60 inches long. Add the landings to the runs for the space a straight ramp takes; a ramp that turns needs 60 by 60 inch landings at the turns.
Worked example: a 24 inch rise at 1:12 is 24 × 12 = 288 inches, 24 feet of ramp. 24 inches is under the 30 inch limit, so it is one run with a landing at each end: 288 + 2 × 60 = 408 inches, 34 feet in a straight line. The rise is over 6 inches, so it needs handrails on both sides.
Ramp slopes in percent and degrees
Run per inch of rise, percentage and angle for the common slopes. 1:12 is the ADA limit; the steeper two are allowed only in existing buildings for small rises (ADA Table 405.2), and 1:20 or flatter is a walking surface, not a ramp.
| Slope | Run per inch of rise | Percent | Degrees | Under the ADA |
|---|---|---|---|---|
| 1:8 | 8 in | 12.5% | 7.13° | Existing sites only, rise 3 in or less |
| 1:10 | 10 in | 10% | 5.71° | Existing sites only, rise 6 in or less |
| 1:12 | 12 in | 8.33% | 4.76° | ADA maximum for a ramp |
| 1:16 | 16 in | 6.25% | 3.58° | Gentler ramp |
| 1:20 | 20 in | 5% | 2.86° | Walking surface, not a ramp |
Runs, landings and handrails
Under section 405 of the 2010 ADA Standards a ramp run rises 30 inches at most, has a level landing at the top and the bottom, and is at least 36 inches wide between handrails. Landings are at least 60 inches long and as wide as the widest run that reaches them. Runs that rise more than 6 inches need handrails, and section 505 puts them on both sides, with 12 inch extensions past the top and bottom of each run.
Home ramps, portable ramps and loading ramps
The ADA Standards are written for public and commercial buildings and government facilities. A ramp at a private home, a portable ramp for a scooter or a loading ramp for equipment may follow other guidance: the local building code, a funding program's rules or the ramp maker's instructions. Choose "Other ratio" for a loading ramp; the calculator gives the length, percentage and angle and leaves out the ADA runs and landings when the slope is steeper than 1:12.
This page is a measuring aid, not a substitute for the local code or the building department.
For home medical equipment and home modification reps: what to write down
Measure the rise at each door the client uses, the width of the door, the space in front of it and where the ramp could turn. Note who will use the ramp and how (a wheelchair, a scooter, a walker), whether it is permanent or portable, and who is paying. Keep health details out of your notes. Read the numbers back before you leave.
Source, read on 2026-10-28. Check the local code before you build:
Building steps beside the ramp? The stair calculator works out the risers and treads, and the concrete calculator the yards for a poured ramp or landing.
More for home medical equipment and home modification reps: Medical device sales, Home improvement sales, Senior living sales.
The rise gets measured on the home visit
So do the door, the space in front of it and what the client wants the ramp to do. Say the measurements out loud as you take them and record the walk-through in ParrotNotes: you get a structured note, a summary and the action items, so the numbers are in the notes when you quote. Free for 100 minutes of recording a month.
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