Retaining Wall Calculator Formula
Understand the math behind the retaining wall calculator. Each variable explained with a worked example.
Formulas Used
Total Blocks
total_blocks = ceil(blocks_per_row * num_rows * 1.1)Blocks per Row
blocks_per_row_out = blocks_per_rowNumber of Rows
num_rows_out = num_rowsVariables
| Variable | Description | Default |
|---|---|---|
wall_length | Wall Length(ft) | 20 |
wall_height | Wall Height(ft) | 3 |
block_length | Block Length(in) | 12 |
block_height | Block Height(in) | 4 |
blocks_per_row | Derived value= ceil(wall_length * 12 / block_length) | calculated |
num_rows | Derived value= ceil(wall_height * 12 / block_height) | calculated |
How It Works
Retaining Wall Block Calculation
Blocks per Row = Wall Length (in) / Block Length
Rows = Wall Height (in) / Block Height
Total = Blocks per Row × Rows × 1.1 (waste)
Worked Example
20 ft long, 3 ft high wall with 12×4 in blocks.
wall_length = 20wall_height = 3block_length = 12block_height = 4
- 01Blocks per row = 240/12 = 20
- 02Rows = 36/4 = 9
- 03Base total = 20 × 9 = 180
- 04With 10% waste = 198 blocks
Ready to run the numbers?
Open Retaining Wall Calculator