Retaining Wall Calculator
Calculate how many blocks you need for a retaining wall project based on wall dimensions and block size.
Formula & Explanation
The retaining wall calculator uses the following formula: 1. Number of courses = ceil(Wall height (inches) ÷ Block height (inches)) 2. Wall width in inches = Wall width (feet) × 12 3. Blocks per course = ceil(Wall width (inches) ÷ Block width (inches)) 4. Total blocks = Number of courses × Blocks per course This provides the number of blocks needed to construct the wall face. Additional blocks may be needed for backfill or reinforcement depending on wall height and soil conditions.
Assumptions
- •Calculation assumes a simple rectangular wall with uniform block size
- •Block size refers to the exposed face dimensions; internal block depths are not factored
- •Result is for the wall face only; backfill materials (gravel, soil) must be calculated separately
- •This calculator is for PRELIMINARY ESTIMATION ONLY
- •For walls over roughly 3-4 feet tall, or walls retaining slopes or surcharge loads, engineering and permits are typically required
- •Drainage, compaction, and proper base preparation are critical for wall longevity and safety
Example Calculation
A 24-inch tall retaining wall that is 10 feet long, built with 12×12 inch blocks, requires 20 blocks (2 courses of 10 blocks each).
Inputs
Results
Common Retaining Wall Block Sizes
| type | height_in | width_in | typical_cost |
|---|---|---|---|
| Standard segmental | 12 | 12 | $5-$15 per block |
| Standard segmental | 12 | 18 | $6-$18 per block |
| Split face | 6 | 12 | $4-$12 per block |
| Split face | 8 | 12 | $5-$14 per block |
| Gravity wall stone | 12 | 18 | $8-$20 per block |
Frequently Asked Questions
Related Calculators
Gravel Calculator
Calculate the volume and quantity of gravel or stone needed for driveways, pathways, and landscaping projects.
Soil Calculator
Calculate fill soil and earth material needed for grade changes, retaining wall backfill, and general landscaping fill.
Paver Calculator
Calculate how many pavers you need for patios, walkways, driveways, and other hardscaping projects.
Topsoil Calculator
Calculate the amount of topsoil needed for new garden beds, raised beds, or lawn renovation projects.