Retaining Wall Block Calculator
How many blocks for a retaining wall
Building a retaining wall? Enter the wall length and finished height to estimate the number of standard retaining-wall blocks needed.
Estimating block count
Enter the wall length and finished height as your two dimensions. A standard block face is about 0.5 ft² (roughly 12" wide × 6" high), so plan on about 2 blocks per square foot of wall face. Add a buried base course and backfill gravel for drainage.
Frequently asked questions
How many retaining wall blocks per square foot?
About 2 standard blocks per square foot of wall face (12×6 inch face).
Do I need gravel behind a retaining wall?
Yes — free-draining gravel behind the wall prevents water pressure from pushing it over.