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Blocks, caps, base gravel and drainage stone for a straight or circular block retaining wall.
With these inputs:
| Result | Value |
|---|---|
| Wall blocks needed | 121 blocks |
| Courses (incl. buried) | 5 |
| Cap blocks | 32 caps |
| Base gravel | 1.83 tons |
| Drainage stone (#57) | 3.42 tons |
| Wall run | 30 ft |
| Blocks per course | 23 |
| Buried depth | 6 in (first course below grade) |
| Exposed wall face | 60 sq ft |
| Leveling pad, 6" compacted crusher run | 1.83 tons |
| Drainage zone, 12" of #57 stone | 2.44 yd³ · 3.42 tons |
| Perforated drain pipe | 30 ft |
| Filter fabric | 120 sq ft |
| Blocks + caps | $660 |
| Stone, pipe & fabric | $191 – $358 |
| Materials total | $851 – $1,017 |
Includes 5% extra blocks for cuts and breakage. Curved walls need more cutting on the inside radius — add another 5%.
Enter the wall length (or the diameter of a round wall), how tall it will stand above the ground, and the block you are using. This calculator adds the buried course, counts blocks and caps, and sizes the two amounts of stone every block wall needs: the crushed-stone leveling pad and the clean drainage gravel behind it.
Divide the wall length by the block length for blocks per course, then multiply by the number of courses — including the buried first course. A 30 ft wall 24 inches tall in 16 x 6 inch block is 23 blocks per course × 5 courses = 115, or about 121 with 5% extra.
At least 6 inches, or about one inch for every eight inches of exposed height, whichever is more. The buried course keeps the base of the wall from kicking out.
A 12 inch wide zone of clean angular stone such as #57, from the leveling pad to about 6 inches below the top, with a perforated drain pipe at the bottom. For a 30 ft wall standing 30 inches tall (36 inches of block with the buried course) that is about 3 cubic yards, or roughly 4.3 tons.
Most residential codes require an engineered design once a wall retains more than 4 feet of soil, and sooner if there is a slope, a driveway or a structure above it. Many towns also require a permit below that height — check locally.
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