Free Online Tool

Retaining Wall Calculator — Estimate Materials Instantly

Calculate retaining wall blocks, cap blocks, gravel base, drainage pipe, geogrid, and concrete footing for any wall project.

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6
Material Types
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Enter your wall dimensions and click Calculate to see material estimates.

Frequently Asked Questions

Calculate the wall area (length x height), then divide by the face area of one block. Standard 8x3x16 blocks cover approximately 2 sq ft each. Add 5% for waste and cuts.
Yes, a compacted gravel base is essential for proper drainage and stability. Typical depth is 6–8 inches for walls up to 4 ft tall, and 12 inches for taller walls. The base should extend at least 12 inches beyond the wall face.
A perforated drainage pipe at the base of the wall is recommended for walls over 3 ft tall. It prevents water pressure buildup behind the wall. The pipe should be wrapped in geotextile fabric and directed to a drainage outlet.
Geogrid is a reinforcing mesh that stabilizes the soil behind retaining walls over 4 ft tall. It extends horizontally into the backfill to distribute lateral loads and prevent wall failure. Not required for short walls under 3 ft.
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