FullCalculator

Retaining Wall Block Calculator

Retaining Wall Block Count

Calculate blocks needed for your retaining wall

Retaining Wall Cost Estimate

Estimate total cost for a retaining wall block project

Formula

Blocks Per Row = Wall Length / Block Length | Courses = Wall Height / Block Height | Total = Rows × Courses × 1.05 | Base Gravel = Length × (Block Depth + 12") / 12 × 0.5'

Frequently Asked Questions

How many retaining wall blocks do I need?
Divide wall length by block length to get blocks per row. Divide wall height by block height to get number of courses. Multiply together and add 5-10% for waste and cuts. Example: 30 ft wall × 3 ft tall with 16" × 6" blocks = 23 blocks/row × 6 courses = 138 blocks + 5% = 145 blocks.
How tall can a retaining wall be without an engineer?
Most building codes allow 3-4 feet without an engineer or permit. Walls over 4 feet typically require a structural engineer, permits, and geogrid reinforcement. Some jurisdictions have stricter limits. Always check with your local building department.

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