Portable and threshold ramps: slope, length and what fits
A ramp is bought by one number, and it is not the length. It is the rise: the vertical distance from the ground to the surface you are trying to reach. Measure that first, in inches, straight up. Everything else on this page follows from it.
How long the ramp needs to be
The figure everyone quotes is 1:12, from the 2010 ADA Standards for Accessible Design: a ramp run no steeper than one inch of rise for every twelve inches of length (section 405.2). In plain terms that is one foot of ramp per inch of rise.
At 1:12, a 6 inch rise needs a ramp 6 feet long.
| Rise | Ramp length at 1:12 |
|---|---|
| 1 in | 1 ft |
| 2 in | 2 ft |
| 4 in | 4 ft |
| 6 in | 6 ft |
| 8 in | 8 ft |
| 12 in | 12 ft |
| 18 in | 18 ft |
| 24 in | 24 ft |
| 30 in | 30 ft |
Thirty inches is where the table stops because the standard stops there too: the rise for any single ramp run is 30 inches at most (section 405.6), with a level landing at the top and bottom of each run.
What that standard does and does not cover
The ADA standard governs public accommodations and commercial facilities. It does not regulate a ramp at a private home, and a folding ramp laid over two steps is not a permanent ramp in its sense at all. We use its numbers because they are the only published ones with a reason behind them, not because your porch has to comply.
Three more figures from the same section are worth knowing before you buy:
| What | Figure | Where it comes from |
|---|---|---|
| Clear width of a ramp run | 36 inches minimum | ADA 2010, section 405.5 |
| Handrails | Required where the rise is over 6 inches | ADA 2010, section 405.8 |
| Steeper than 1:12 | Allowed only in existing buildings where space forces it | ADA 2010, section 405.2, exception |
Two of those are worth holding against any portable ramp you look at. Neither ramp on this page has handrails, and the usable width of a folding ramp is a figure on the maker's page: compare it with 36 inches. That is the honest limit of the category. A portable ramp is a way over a short rise, and not a substitute for a built ramp at a tall entrance.
The maker of the folding ramp below gives the same advice from the other direction: check the user guide for the wheelchair or scooter itself, because the equipment has its own stated limit on incline.
Threshold ramp or portable ramp
A threshold ramp is for a rise of a few inches: a door sill, a sliding door track, a single low step. The number it is sold by is the rise it is made for, and it has to match yours.
A portable folding ramp covers one to several steps and folds for carrying. Here length is the number, taken from the table above, and the weight of the ramp itself matters as much as the weight it carries, because somebody has to set it down.
Maker-rated to 1,500 lb, for a rise of up to 2 inches, 16 inches long by 43½ wide. Solid rubber, one piece, nothing to assemble.
Check price on Amazon (paid link)Maker-rated to 800 lb. Folds in three and separates into two sections to carry. By the table above, 8 feet suits a rise of about 8 inches.
Check price on Amazon (paid link)Straight up from the ground to the top surface, in inches. Not the length of the steps.
Work out the length
Capacity and dimensions are the makers' own published figures, read on 1 October 2026: EZ-ACCESS and Discount Ramps, which makes the Silver Spring ramp. We have not tested either ramp. The slope figures are from the 2010 ADA Standards, chapter 4, section 405.
Three checks before it arrives
- Add up the load. The capacity has to cover the chair or scooter, the person in it, and anything they carry. The weight of the chair is in its own manual.
- Look at where the bottom lands. An 8 foot ramp needs 8 feet of flat ground in front of the steps, plus room to line up with it.
- Decide who lifts it. The weight of the ramp itself is on the maker's page for each length. Check it against the person who will be carrying it.
For the doorway itself, which walking aid suits which stage covers what rolls over a threshold and what catches on it. For steps you cannot ramp, the stairs guide ranks what is left.