Rip Rap Calculator

Step 1: Measure the Area

Take accurate measurements of the area to be protected:

• Length: measure along the shoreline or slope
• Width: measure from the water edge to the top of protection needed
• Depth: varies by application (typically 12-24 inches)
• For irregular areas: break into sections and calculate separately

Step 2: Calculate Volume

Use the volume formula and convert to practical units:

• Volume (cubic feet) = Length x Width x Depth
• Cubic yards = Cubic feet / 27
• Weight (tons) = Cubic yards x 1.5

Example: 100' x 10' x 1.5' = 1,500 cubic feet = 55.6 cubic yards = 83.3 tons

Step 3: Choose Stone Size

Select appropriate stone size based on your application:

• Small (6-12"): Light erosion, decorative applications - $25/yard
• Medium (12-18"): Moderate water flow, general protection - $35/yard
• Large (18-24"): Heavy water flow, severe erosion - $45/yard

Common Applications

Installation Best Practices

• Prepare the slope to proper grade and remove debris
• Install geotextile fabric as a base to prevent undermining
• Place stones from bottom to top of the slope
• Ensure stones interlock properly for stability
• Use toe protection at the waterline for maximum effectiveness
• Consider drainage behind rip rap for long-term stability

Benefits of Rip Rap

• Immediate and long-lasting erosion protection
• Permeable design allows water infiltration
• Natural appearance blends with environment
• Low maintenance once properly installed
• Flexible design adapts to ground movement
• Cost-effective compared to concrete alternatives

Planning Tips

• Add 10-15% extra material for settling and irregular coverage
• Consider access for delivery trucks and equipment
• Check local regulations and permit requirements
• Plan installation during dry weather when possible
• Consider hiring professionals for large or critical installations
• Factor in geotextile fabric and filter material costs