Retaining Wall Calculator
Count retaining wall blocks per course and total, plus cap blocks and gravel backfill volume.
Processed locally in your browser — nothing is uploaded.
Enter the wall dimensions to estimate blocks.
About Retaining Wall Calculator
From the wall length and height and a block face size (12 × 4 in default), it computes blocks per course, the number of courses, and the total with waste. It adds one course of cap blocks and sizes the gravel backfill assuming a 12 in drainage zone behind the full wall face.
Common uses
- Order block and drainage rock for a garden terrace wall
- Compare block counts between 12 in and 16 in block formats
Example
Input
20 ft long × 3 ft tall, 12×4 in blocks, 10% waste
Output
20/course × 9 courses = 180 → buy 198 + 20 caps · 2.22 yd³ backfill
Limitations
- Walls above ~3–4 ft typically require engineering and permits
- Ignores the buried base course and leveling pad — add one course and base gravel