Retaining Wall Calculator

This calculator determines material requirements by evaluating the physical dimensions of your proposed wall and standard block sizes. First, the total number of standard wall blocks is calculated by dividing the wall height and width by the individual block dimensions, rounding up to ensure you have enough material (Blocks = ceil(Wall Height / Block Height) * ceil(Wall Width / Block Width)). Cap stones are computed similarly based on the top linear run. Drainage gravel backfill volume is calculated using standard rectangular dimensions (Backfill = Length * Thickness * Height), which is then multiplied by your gravel density to find the total weight and overall material cost.

Imagine you are planning to build a retaining wall that is 3 feet high and 30 feet wide. Let us assume standard concrete blocks are 0.5 feet high and 1 foot wide. First, calculate the vertical courses needed: ceil(3 / 0.5) = 6 rows. Next, calculate the blocks per row: ceil(30 / 1) = 30 blocks. Multiplying these together gives 180 standard wall blocks. For the top layer, you will need 30 cap blocks. If your backfill thickness is 1 foot behind the entire 30-foot length, your gravel volume is 30 ft * 1 ft * 3 ft = 90 cubic feet. By factoring in gravel density and individual material pricing, you can fully budget your project supplies with confidence.

Always order 5 to 10 percent more blocks and cap stones than your final calculated total to account for cuts, breakages, and uneven grading at the job site. Ensure your gravel backfill is clean, washed angular stone rather than round pea gravel, as angular stones lock together to provide superior structural stability and drainage.