Retaining Wall Calculator — Free Online Tool

How to use Retaining Wall Calculator

Estimate the face blocks and whole pallets required for a rectangular retaining wall using wall length, exposed height, block face size, joints and waste allowance.

1. Enter measured wall length and exposed height.
2. Enter the actual block face width and height, not packaging dimensions.
3. Add any joint gap used by the manufacturer and spare-block allowance.
4. Confirm pallet coverage, buried courses and the structural wall design separately.

Important: Never use a block-count estimate as a structural design or construction approval.

Formula and methodology

Block courses = ceil((wall height + joint) ÷ (block height + joint)). Blocks per course = ceil((wall length + joint) ÷ (block length + joint)). Face blocks = courses × blocks per course.

The interactive calculations depend on the inputs, units and assumptions you provide. Display values are rounded for readability, but calculations use unrounded input values where applicable.

Worked example

A 10-foot-long by 4-foot-high face made from 16 × 8 inch block faces with no joints needs 8 blocks per row × 6 rows = 48 blocks, before waste. This does not include buried base courses.

Try entering your own measurements above to reproduce this calculation and understand each result.

Frequently asked questions