Ramp Calculator
Rise to ramp: run at your slope ratio, the 30-in-per-run landing law, handrail footage and the footprint before you dig.
Ramp Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Straight runs — switchbacks add landing geometry by hand.
- No cross-slope or edge-protection take-off.
- Cost band covers the run, not rails or landings detail.
In short: A 24-in porch rise at 1:12: a 288-in run — 24 ft at 8.33% and 4.76° — one run inside the 30-in rise cap, two 60-in landings, 56 ft of handrail both sides with 12-in extensions, a 34-ft footprint, $1,800-3,600 built. Steeper than 1:8 is refused.
Formula
run = rise × X — at 1:12, 12 in of ramp per inch of rise
grade = 100 ÷ X %; angle = atan(1 ÷ X)
runs = ⌈rise ÷ 30⌉; landings = runs + 1, all 60×60 in
rails = (run + 24 in extensions) × 2 sides, when rise > 6 in
[('1:12', 'the ADA ceiling — 8.33%, 4.76°'), ('30 in', 'max rise per run before a landing (ADA 405.6)'), ('60×60', 'landing minimum, top, bottom and turns'), ('36 in', 'clear width between handrails')]
Worked Example
- Measure the rise from ground to landing surface.
- Pick the ratio — 1:12 unless the yard refuses.
- Multiply for the run; divide the rise by 30 for runs.
- Place a 60-in landing at top, bottom and each turn.
- Rail both sides past a 6-in rise; price the band.
24 in at 1:12: 288-in run (24 ft), 8.33%, 4.76°, one run, two landings, 56 ft of rail, 34-ft footprint, $1,800-3,600. A 66-in rise needs 3 runs and 2 intermediate landings.
Strengths & Limits Of This Model
Where this engine is strong
- The 30-in/landing ladder computed, not remembered
- Rail footage with extensions, both sides
- Refuses to draw a ramp a chair cannot climb
Where it stops
- Straight-run geometry only
- Concrete take-off left to the Concrete pages
Practical Use Cases
Porch access
The classic 1:12 entry ramp.
Permit drawings
Runs, landings, rails on one sheet.
Yard checks
Does 24 ft of ramp fit the lot?
Thresholds
Short rises at doors and garages.
Budgeting
Wood vs modular vs concrete bands.
Methodology & Editorial Standards
Ramp geometry is one multiplication and one code ladder. Run = rise × ratio at the entered 1:X (free-entry 8-40; steeper refused — 1:8 is the residential floor, and a chair cannot climb past it). Grade and angle are the exact 100/X and atan(1/X). Runs ceil at 30 in of rise apiece with runs+1 landings at 60 in; handrails compute both-sides footage with 12-in extensions once rise passes 6 in; cost shows the researched $75-150/ft band over the run. Zero rise refused.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Ramp Calculator — 8 Expert FAQs
8 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How long should a wheelchair ramp be?
Twelve inches of run per inch of rise for accessible routes — a 24-in porch needs 24 ft of ramp. Steeper than 1:12 fails ADA; IRC residential tolerates 1:8 when space truly forces it.
How steep is too steep?
1:12 (8.33%, 4.76°) is the ceiling for accessible routes; 1:8 is the residential pinch. Below 1:8 this page refuses to draw — the chair cannot climb it.
When does a ramp need a landing?
Every 30 inches of rise, at minimum — plus a 60×60-in landing at top and bottom and at every direction change. A 66-in rise is three runs and two intermediate landings.
Does a 24-inch ramp need handrails?
Yes — rise over 6 in requires them on both sides, 34-38 in high, extending 12 in past each end. That is 56 linear feet of rail on a 24-ft run.
How wide must a ramp be?
36 inches clear between the handrails; 42-48 in overall once rails and edge protection are built. Cross slope stays under 1:48 so no one drifts sideways.
What does a ramp cost to build?
Roughly $75-150 per foot of run built — pressure-treated low, aluminum modular mid, poured concrete high; concrete ramps commonly land $1,200-3,500 installed.
Can I just pour a concrete ramp?
Yes — 4 in residential, 5-6 in commercial, 3,000-4,000 psi, #4 rebar on a 12-18 in grid over compacted base. The geometry on this page is identical; only the forming changes.
What concrete do ramps use?
3,000-4,000 psi — commercial and freeze-thaw regions at the top of that band, air-entrained. Residential slabs run 4 in thick; wheelchair-rated commercial runs 5-6.