Retaining Wall Calculator
Work out how many retaining blocks and courses you need for a wall, plus the cost — from the wall length and height. Free, instant, no sign-up.
Wall
Block & price
Your retaining wall estimate
Wall face area10,0 m²
Courses (rows)5 courses
Blocks to buy (incl. waste)176 blocks
Estimated block costR 7 920
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Create a free account →How the retaining wall calculation works
wall area (m²) = length × height block face (m²) = block length × block height blocks = ⌈wall area ÷ block face × 1.05⌉ courses = ⌈wall height ÷ block height⌉
FAQ
- How do I calculate retaining wall blocks?
- Work out the wall face area (length × height), divide by the face area of one block (its length × height), and add about 5% for cuts and breakage. This calculator does it and also shows the number of courses.
- How many courses (rows) will my wall be?
- Divide the wall height by the block height and round up. A 1 m wall in 200 mm blocks is 5 courses.
- Do I need a base and drainage behind a retaining wall?
- Yes — a compacted gravel base and free-draining backfill with drainage are essential for a lasting wall. Walls above about 1 m often need engineering sign-off.
- Does this include the base and backfill?
- This estimates the wall blocks. Create a free BuilderBuddi account to build the full retaining-wall estimate with base, drainage stone, and labour.
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