Retaining Wall Calculator

A 10 ft long, 2 ft tall wall needs 44 blocks (including the buried first course) and about 0.4 cubic yards of base gravel — enter your wall's length, height, and block size to get a materials list.

Wall length (ft)

Exposed wall height (ft)

Block width (in)

Block height (in)

Base gravel depth (in)

Base width (ft)

Waste margin (%)

Courses

Blocks

Base gravel

0.38 yd³

Includes the first course buried 6 in below grade.

Wall blocks
44 blocks
per block for Wall blocks
Cap blocks
8 pcs
per pc for Cap blocks
Base gravel
0.38 yd³
per yd³ for Base gravel

Enter your local prices to see an estimated cost.

How we calculate this

The first course goes below grade: we bury it 1 in for every foot of exposed wall height, or 6 in, whichever is greater — the common industry guideline for flat ground in front of the wall. Courses = (exposed height + buried depth) ÷ block height, rounded up. Blocks per course = wall length ÷ block width, rounded up. We multiply courses × blocks per course, add your waste margin, and add one cap unit per block in the top course. Base gravel = length × trench width (2 ft by default) × base depth (6 in by default). Always follow your block manufacturer's instructions — they vary by product.

This covers low, gravity block walls only (roughly 3 ft or under) — not engineering for tall or load-bearing walls. Anything taller, holding back a slope, or near a structure needs a professional and likely a permit.

Estimates only. Check local codes and product labels. Read our full disclaimer.