Calculate blocks, backfill gravel, and drainage materials for a retaining wall.
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How to Use This Calculator
<h4>How to Use</h4><ol><li>Enter the total wall length and desired height.</li><li>Enter the block dimensions (or use the defaults for standard blocks).</li><li>Adjust waste percentage if needed.</li><li>Review block count, backfill, drainage, and fabric quantities.</li></ol><h4>Tips</h4><ul><li>Most retaining wall blocks are 6×18 in (150×450 mm).</li><li>Walls over 4 ft (1.2 m) typically need engineering approval.</li><li>Always include drainage behind the wall to prevent hydrostatic pressure buildup.</li></ul>
Common Questions
How high can I build without an engineer?
Most jurisdictions allow gravity retaining walls up to 4 feet (1.2 m) without engineered design. Always check local building codes.
What is geotextile fabric for?
Geotextile fabric separates the backfill gravel from the surrounding soil, preventing fine particles from clogging the drainage system.
Do I need a footing for a retaining wall?
Most segmental retaining walls sit on a compacted gravel base (6–12 inches / 150–300 mm deep). A concrete footing is typically needed for walls over 4–6 feet.