Retaining Wall Calculator

Calculate the number of blocks needed for a retaining wall.
Calculator
Enter your values
Results
Blocks Needed
84
For 60.0 sq ft wall
Project Analysis
Wall planning details

Base Course

Remember to bury the first course of blocks for stability. For a 3ft wall, at least 4 inches (approx 1 course) should be buried.

Drainage

Plan for 12 inches of drainage gravel behind the wall. For this 20ft wall, you'll need approx 2.2 cubic yards of gravel.

Cap Stones

You will need approx 14 cap stones to finish the top of the wall.

How to Use

Step-by-step instructions
  1. 1Enter the length and height of the wall (in feet).
  2. 2Enter the dimensions of the block (in inches).
  3. 3The calculator will estimate the total blocks needed.

Block Count

Calculates the number of blocks needed to cover the wall area, including 5% wastage.
Blocks = Wall Area / Block Area

Variables:

Wall AreaLength x Height
Block AreaLength x Height of one block

Example

20ft Wall

Inputs:

Length:20 ft
Height:3 ft
Block:18" x 6"

Steps:

  1. 1.Wall Area = 60 sq ft
  2. 2.Block Area = (18 * 6) / 144 = 0.75 sq ft
  3. 3.Blocks = 60 / 0.75 = 80 blocks
  4. 4.+5% Wastage = 84 blocks
Result:
84 Blocks

Frequently Asked Questions

Does this include cap stones?

No, this calculates the main wall blocks only. Cap stones would be calculated based on linear footage.