How to calculate a ramp length
Use the calculator in this order:
- Enter Rise (height to climb) and choose its unit.
- Choose Slope format: Ratio (1:X), Percent grade (%), or Angle (degrees).
- Enter the numeric value in Slope value.
- Review the prefilled Top landing length and Bottom landing length. Both start at
5 ft; replace them with your measurements or enter0to exclude a landing. - Click Calculate. The result section appears only after a valid calculation.
Enter slope and landing values correctly
For Ratio (1:X), enter only the X value in Slope value. For a 1:12 slope, enter 12, not 1:12. Percent grade (%) accepts a percentage, while Angle (degrees) accepts the angle from horizontal.
Rise (height to climb) and both landing lengths support inches, feet, centimeters, or meters. Select units independently for each length field. The visible defaults are 12 for Slope value and 5 ft for each landing.
What the result shows
After Calculate succeeds, the result shows Ramp (sloped) length, Slope ratio, Slope grade and angle, and Total path (ramp + landings).
The Formula used block displays the calculation formulas. The table lists entered, converted, and intermediate values; it does not contain a separate formula for every row. Displayed values are formatted and rounded for presentation.
Ramp length formulas
The calculator uses these relationships, with length inputs converted to inches internally:
Run = Rise x Slope ratio, where X is the value in1:X.Ramp (sloped) length = sqrt(Rise^2 + Run^2).Slope % = 100 / XandAngle = atan(1 / X).Total path length = Ramp length + Top landing + Bottom landing.
Validation and calculation limits
Calculation stops and an error appears when a value is missing, not numeric, or outside the accepted range:
- Rise:
0.01to600in the selected unit. - Ratio (1:X):
0.5to100. - Percent grade (%):
0.5to200. - Angle (degrees):
0.1to80. - Each landing length:
0to500in its selected unit.
Calculation assumptions and limitations
- The model uses one straight ramp run at a constant slope with flat top and bottom landings.
- Landing lengths are added directly to the sloped ramp length.
- It does not model switchbacks, intermediate landings, handrails, cross-slope, or surface material.
- It does not look up ADA, accessibility, or building-code requirements.
The interface uses 1:12 as an example and default context. That is not a universal legal requirement; applicable rules vary by jurisdiction and use case. Confirm requirements with your local code and a qualified professional.
Copy or download the result
Click Copy result to place the plain-text summary on your clipboard. Click Download result (.txt) to save ramp-calculator-result.txt. The summary includes inputs, converted values, calculated outputs, formulas, and the compliance disclaimer.
Calculation privacy and page data
The calculator script performs the calculation in your browser and does not submit the rise, slope, or landing values. The page also loads Ahrefs and Google Analytics scripts and includes a separate subscription form that submits an email address to /assets/subscribe.php.
Frequently Asked Questions
What is the ramp length formula?
Run = Rise x Slope ratio, and Ramp (sloped) length = sqrt(Rise^2 + Run^2). Add the top and bottom landing lengths to the sloped length for total path length.
How do I enter the slope - ratio, percent, or degrees?
Choose Ratio (1:X), Percent grade (%), or Angle (degrees). For a ratio, enter only X in Slope value; enter 12 for 1:12. Percent uses rise divided by run times 100, and degrees is measured from horizontal.
Does this tool guarantee my ramp meets ADA or building-code requirements?
No. It performs a geometry calculation from the values you enter. Maximum slope ratios, landing sizes, handrail requirements, and other rules vary by jurisdiction and use case; confirm them with your local code and a qualified professional.
What units are supported?
Rise and both landing lengths each accept inches, feet, centimeters, or meters, chosen independently for each field.
Does this tool fetch live data or give certified advice?
No. It performs one calculation using the values you type. It does not fetch code tables, accessibility standards, or supplier data, and it is not a certified engineering, accessibility, or compliance determination.