Retaining Wall Blocks: Counting by Face Area
Block counts start with the wall face, not the wall volume. This post shows the face-area division and the cutting allowance.
What is the Retaining Wall Blocks Calculator?
Enter the wall length and height and the face area of one block, and the tool works out the face area, divides by block face area, adds a 10 percent allowance for cuts and breakage, and rounds up. The allowance is shown separately.
How to use it
- Measure the wall length and height in metres.
- Enter the face area of one block.
- Click Count Blocks.
Worked example
6 m by 1 m gives a 6 sq m face, needing 120 blocks exactly, or 132 with the 10 percent allowance.
Does this cover the footing or drainage?
No. Footing, drainage stone, and geogrid are separate materials with their own quantities.
Frequently asked questions
Do tall walls need engineering?
Walls above about a metre often need professional design and local approval, so check rules before building.
What about cap blocks?
Cap blocks are counted separately by wall length, not by face area.