Ramp Slope Calculator
Calculate ramp slope percentage, rise-to-run ratio, angle, required run for a target ratio, sloped length, surface area and material cost.
Default project preview
8.33 %
Required target run
30 ft
Run margin
+0 ft
Sloped ramp length
30.1 ft
Surface order area
154.5 ft²
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Vertical rise
Enter this project assumption in in. The current imperial default is 30 in.
Available horizontal run
Enter this project assumption in ft. The current imperial default is 30 ft.
Target run per unit rise
Enter this project assumption in :1. The current imperial default is 12 :1. Minimum: 1.
Ramp width
Enter this project assumption in ft. The current imperial default is 4 ft.
Landing length
Enter this project assumption in ft. The current imperial default is 5 ft. Minimum: 0.
Surface allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 50.
Stock or module length
Enter this project assumption in ft. The current imperial default is 8 ft.
Surface price per area
Enter this project assumption in per ft². The current imperial default is 12 per ft². Minimum: 0.
How to read the outputs
Required target run
for a 12:1 target. Default preview: 30 ft.
Run margin
available beyond target. Default preview: +0 ft.
Sloped ramp length
excluding landing. Default preview: 30.1 ft.
Surface order area
landing and allowance included. Default preview: 154.5 ft².
Length modules
8 ft each. Default preview: 5.
Surface cost
entered area rate. Default preview: $1,853.49.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Slope percent = rise ÷ horizontal run × 100. Ratio = run ÷ rise. Required run = rise × target ratio. Sloped length uses the Pythagorean theorem.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 30, 2026
Use this calculator to relate vertical rise, horizontal run, slope percentage and ratio for a straight ramp. It supports layout checks but does not certify accessibility, landings, handrails or structural design.
Calculation steps
- 1Convert rise and run to the same units.
- 2Divide rise by horizontal run.
- 3Express the result as a percentage and as a 1:n ratio.
- 4Calculate ramp length from the hypotenuse if needed.
Worked numerical example
A 24 in rise over a 24 ft horizontal run equals 2 ft ÷ 24 ft = 8.33%, or roughly a 1:12 slope.
Purchasing and rounding
No product quantity is generated. Use the resulting geometry in separate concrete, decking, railing or surface calculators.
Interpret the result
A smaller percentage and larger ratio denominator indicate a gentler ramp. Compliance depends on the full route, not slope alone.
Page-specific assumptions
- Straight single-slope ramp.
- Horizontal run excludes landings.
- Dimensions are finished-surface measurements.
- No vertical curves.
Common mistakes
- Using ramp surface length as horizontal run.
- Mixing inches and feet.
- Ignoring landings and transitions.
- Claiming accessibility compliance from slope alone.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
FAQ
Ramp Slope Calculator questions
What does a 1:12 ramp ratio mean?+
It means 12 units of horizontal run for every 1 equal unit of vertical rise.
Is the sloped length the same as horizontal run?+
No. The sloped surface is slightly longer because it follows the hypotenuse.
Does this confirm accessibility compliance?+
No. Compliance also depends on landings, handrails, clear width, cross slope, edges and jurisdiction-specific rules.