What Is a Retaining Wall Calculator?
A retaining wall calculator is a tool that provides a material list for building a gravity-based, interlocking block retaining wall. It estimates the number of wall blocks and cap blocks needed, as well as the volume of gravel required for the base and backfill drainage zone, which are critical for a stable and long-lasting wall.
How to Use This Calculator
- Enter the total length and finished height of your wall in feet.
- Select the type of block you will be using, or enter custom dimensions.
- Indicate whether you will be using cap blocks for the top course.
- Optionally, enter the cost per block and per cubic yard of gravel for a budget estimate.
- Click "Calculate" to generate your full material shopping list.
Understanding Your Retaining Wall Estimate
- Wall Blocks: The number of interlocking blocks needed to build the wall to your specified dimensions, including a waste factor.
- Cap Blocks: The finished stones that go on the top row of the wall. The quantity is based on the wall's length.
- Base Material: The volume of crushed stone needed for the critical 6-inch deep compacted leveling pad.
- Backfill Material: The volume of drainage gravel needed for the 12-inch zone behind the wall to manage water pressure.
Warning: For Walls Under 4 Feet ONLY
This calculator is NOT for walls taller than 4 feet. Such walls require professional engineering. Learn more in our Retaining Wall Guide.