🛝 Ramp Calculator
Calculate ramp length, angle, and check ADA compliance
Vertical rise from bottom to top
Ramp angle (ADA compliant: 4.76° for 1:12 ratio)
How to Use This Calculator
Select Calculation Type
Choose whether to calculate from height and angle (most common) or from ramp length and angle. This determines which inputs you'll provide.
Enter Dimensions
If calculating from height: enter the vertical rise (height) in inches and the desired ramp angle in degrees. If calculating from length: enter ramp length and angle.
Calculate and Review
Click "Calculate Ramp" to see ramp length, height, horizontal run, angle, and ADA compliance status. Use this information for ramp construction and compliance checking.
Check Compliance
Review ADA compliance status. For ADA compliance, ramp ratio should be 1:12 or better (4.76° or less). For gentle slopes, ratio should be 1:20 or better (2.86° or less).
Formula
Ramp Length = Height ÷ sin(Angle)
Horizontal Run = Height ÷ tan(Angle)
Height = Ramp Length × sin(Angle)
Ratio = Ramp Length ÷ Height
ADA Compliant: Ratio ≤ 12 (1:12 ratio = 4.76° angle)
Example 1: ADA Compliant Ramp (36" height, 4.76° angle)
Step 1: Convert angle to radians: 4.76° = 4.76 × π/180 = 0.083 radians
Step 2: Calculate ramp length: 36 ÷ sin(4.76°) = 432 inches (36 feet)
Step 3: Calculate horizontal run: 36 ÷ tan(4.76°) = 431.3 inches
Step 4: Calculate ratio: 432 ÷ 36 = 12:1 (ADA compliant)
Example 2: Gentle Slope (30" height, 2.86° angle)
Step 1: Calculate ramp length: 30 ÷ sin(2.86°) = 600 inches (50 feet)
Step 2: Calculate ratio: 600 ÷ 30 = 20:1 (gentle slope, ADA compliant)
About Ramp Calculator
The Ramp Calculator is an essential tool for contractors, builders, architects, and homeowners who need to accurately calculate ramp dimensions and verify ADA compliance for ramp installations. This calculator eliminates guesswork by providing precise ramp length, angle, and compliance calculations based on height or length and angle, helping you build ramps that meet accessibility standards.
When to Use This Calculator
- Ramp Construction: Calculate ramp length and dimensions for new ramp installations
- ADA Compliance: Verify ADA compliance for ramp projects (1:12 ratio or better)
- Accessibility Planning: Plan accessible ramps for buildings and structures
- Contractor Estimates: Quick reference for contractors bidding ramp projects
- Building Permits: Calculate dimensions needed for building permits and inspections
Why Use Our Calculator?
- ✅ Accurate Calculations: Precise trigonometric calculations for ramp dimensions
- ✅ ADA Compliance Check: Automatically checks ADA compliance (1:12 ratio)
- ✅ Multiple Calculation Methods: Calculate from height or length
- ✅ Comprehensive Results: Shows ramp length, height, horizontal run, and angle
- ✅ Compliance Indicators: Clear visual indicators for ADA and gentle slope compliance
- ✅ Time Savings: Instant calculations eliminate manual math and measurements
ADA Compliance Guidelines
ADA Standards: The Americans with Disabilities Act (ADA) requires ramps to have a maximum slope of 1:12 (4.76°). This means for every 1 inch of vertical rise, there must be at least 12 inches of ramp length. The calculator automatically checks this compliance.
Gentle Slopes: For easier accessibility, ramps with a 1:20 ratio (2.86°) are recommended for wheelchairs and mobility devices. These gentler slopes are easier to navigate but require more length.
Landings: ADA also requires level landings at the top and bottom of ramps, and at intervals for long ramps (every 30 feet for 1:12 ramps).
Tips for Best Results
- ADA Compliance: For ADA compliance, use 1:12 ratio (4.76° angle) or better
- Gentle Slopes: For easier access, use 1:20 ratio (2.86° angle) or better
- Measure Accurately: Measure vertical rise accurately for precise calculations
- Include Landings: Plan for level landings at top, bottom, and intervals
- Building Codes: Check local building codes for additional requirements
- Materials: Consider ramp materials (concrete, wood, metal) in planning
Frequently Asked Questions
What is ADA compliant ramp ratio?
ADA compliant ramp ratio is 1:12, meaning for every 1 inch of vertical rise, there must be at least 12 inches of ramp length. This equals a 4.76° angle. The calculator automatically checks this compliance.
How long should a ramp be for 36 inches of height?
For ADA compliance (1:12 ratio), a 36-inch height requires a 432-inch (36-foot) ramp. For a gentle 1:20 ratio, it requires a 720-inch (60-foot) ramp. Use the calculator with your specific height and angle for accurate calculations.
What angle should a ramp be?
For ADA compliance, ramp angle should be 4.76° or less (1:12 ratio). For easier accessibility, 2.86° or less (1:20 ratio) is recommended. Steeper ramps are difficult or impossible for wheelchairs to navigate.
Do I need landings on ramps?
Yes! ADA requires level landings at the top and bottom of ramps, and at intervals for long ramps (every 30 feet for 1:12 ramps). Landings should be at least 60 inches long and as wide as the ramp.
What's the difference between ramp length and horizontal run?
Ramp length is the distance along the ramp surface (the diagonal), while horizontal run is the horizontal distance the ramp covers. Ramp length is always longer than horizontal run due to the angle.
Can I use this calculator for wheelchair ramps?
Yes! This calculator is designed for wheelchair ramps and accessibility projects. It checks ADA compliance and calculates dimensions suitable for wheelchairs and mobility devices.