Ramp Calculator - Calculate Slope, Length & ADA Compliance
Free ramp calculator to determine ramp length, slope ratio, angle, and ADA compliance for wheelchair accessibility and construction projects
Ramp Calculator
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What is a Ramp Calculator?
A ramp calculator is a free construction tool that helps you design wheelchair ramps and accessibility ramps by calculating the proper dimensions, slope ratio, and ADA compliance status. It uses the rise (vertical height) and desired slope to determine the required ramp length and run distance.
This calculator helps with:
- ADA compliance - Ensure your ramp meets accessibility standards with 1:12 slope ratio
- Wheelchair accessibility - Calculate safe, comfortable ramp slopes for wheelchair users
- Building codes - Determine if your ramp design meets local building requirements
- Material planning - Estimate lumber and materials needed for construction
- Cost estimation - Plan your ramp construction budget accurately
Planning deck accessibility? Our Lumber Calculator helps estimate materials needed. Also check our Drywall Calculator for wall construction and Paint Calculator for finishing touches.
How Ramp Slope Calculations Work
Ramp calculations are based on the Pythagorean theorem and slope ratios:
Key Formulas:
- Ramp Length = √(rise² + run²)
- Run = rise × slope ratio
- Slope Angle = arctan(rise ÷ run) × 57.2958
- Slope Percentage = (rise ÷ run) × 100
Example: For a 24-inch rise with 1:12 ADA slope:
- Run = 24 × 12 = 288 inches (24 feet)
- Length = √(24² + 288²) = 289 inches (24.08 feet)
- Angle = arctan(24 ÷ 288) = 4.76°
- Percentage = (24 ÷ 288) × 100 = 8.33%
ADA Ramp Requirements
Maximum Slope: 1:12
The ADA requires a maximum slope of 1:12, meaning 1 inch of rise for every 12 inches of run (4.76° angle).
Minimum Width: 36 inches
Ramps must be at least 36 inches wide between handrails to accommodate wheelchairs.
Landing Every 30 inches
A level landing (60" × 60" minimum) is required for every 30 inches of vertical rise.
Handrails Required
Handrails are required on both sides if the rise is greater than 6 inches or the run exceeds 72 inches.
Edge Protection
Ramps must have edge protection (curbs or barriers) to prevent wheelchairs from slipping off.
Need materials for ramp construction? Use our Concrete Calculator for foundations and Plywood Calculator for decking materials.
How to Use This Ramp Calculator
Measure Rise
Measure the vertical height from ground to the top surface in inches
Select Slope Ratio
Choose slope ratio (1:12 for ADA compliance or custom)
Enter Ramp Width
Input desired ramp width (minimum 36" for ADA)
Get Results
View ramp length, slope angle, and ADA compliance status
Benefits of Using Ramp Calculator
- • ADA Compliance: Ensure your ramp meets federal accessibility standards.
- • Safety Planning: Calculate proper slope angles for safe wheelchair access.
- • Material Estimation: Determine exact lumber lengths needed for construction.
- • Cost Budgeting: Plan project costs with accurate dimension calculations.
- • Code Compliance: Verify your design meets local building codes and regulations.
- • Time Savings: Quickly calculate complex measurements without manual calculations.
Types of Ramps
Straight Ramps
Simple, direct ramps without turns. Best for shorter rises and when space allows.
Switchback Ramps
Ramps with 180° turns and landings. Used when space is limited or rise is significant.
Modular Ramps
Pre-fabricated aluminum or steel ramps. Easy to install, portable, and reconfigurable.
Permanent Ramps
Custom-built wood or concrete ramps. Designed for long-term use and integrated with structures.
Building a deck or stairs? Our Stair Calculator and Flooring Calculator provide accurate material estimates.
Factors That Affect Ramp Design
1. Available Space
Limited horizontal space may require switchback designs or steeper slopes (if permitted).
2. User Needs
Consider whether users will be self-propelled or assisted, affecting optimal slope.
3. Weather Conditions
Snow, ice, and rain require proper drainage, non-slip surfaces, and possibly covered designs.
4. Building Codes
Local codes may have stricter requirements than ADA standards, especially for residential use.
Frequently Asked Questions (FAQ)
Q: What is the ADA compliant ramp slope ratio?
A: The ADA requires a maximum slope of 1:12, meaning for every 1 inch of vertical rise, you need 12 inches (1 foot) of ramp length. This equals approximately 4.76 degrees.
Q: How do I calculate the length of a ramp?
A: Use the Pythagorean theorem: Ramp Length = √(rise² + run²). For a 24-inch rise with 1:12 slope, the run is 288 inches, so length is √(24² + 288²) = 289 inches.
Q: What is the maximum rise for a ramp without a landing?
A: ADA guidelines require a level landing for every 30 inches of vertical rise. The maximum rise without a landing is 30 inches for commercial applications.
Q: Can I build a steeper ramp for temporary use?
A: For temporary or non-public use, you can use steeper slopes like 1:8 (7.13°), but these are harder to navigate. Always check local codes and prioritize safety.