Retaining Wall Calculator

Calculate blocks, cap stones, gravel backfill, and drainage pipe needed for a retaining wall. Enter wall dimensions and block specifications.

🧱 Retaining Wall Calculator

Results

Rows9 rows
Blocks per Row20 blocks
Total Blocks180 blocks
Cap Blocks20 blocks
Gravel Backfill0.7 cu yd
Drainage Pipe20.00 ft

πŸ’‘ How to Estimate Retaining Wall Materials

Retaining wall block calculators work by dividing the wall face area by the face area of a single block. Standard landscape blocks are 12 inches long Γ— 4 inches tall, requiring 3 blocks per linear foot per row. Walls over 4 feet typically need engineering review.

Critical materials beyond blocks include: gravel backfill behind the wall (provides drainage and reduces hydrostatic pressure), perforated drainage pipe at the base, landscape fabric between backfill and soil, and cap blocks (adhesive-set) for the top course.

A 20 ft Γ— 3 ft retaining wall with 12Γ—4 blocks = 9 rows Γ— 20 blocks/row = 180 wall blocks + 20 cap blocks. Add 0.7 cu yd of gravel backfill and 20 ft of perforated drain pipe.

Retaining Wall Calculator FAQ

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