Retaining Wall Block Calculator
Calculate how many blocks you need for a retaining wall based on wall length, height, and block size.
Blocks Needed
Retaining wall blocks are calculated by determining how many rows high and how many blocks long your wall will be.
Rows = Wall Height / Block Height
Blocks Per Row = Wall Length / Block Length
Total Blocks = Rows x Blocks Per Row
Common block sizes:
- Standard: 12" L x 4" H x 8" D (30 x 10 x 20 cm)
- Large: 18" L x 6" H x 12" D (45 x 15 x 30 cm)
- Extra large: 24" L x 6" H x 12" D (60 x 15 x 30 cm)
Tips:
- Add 5-10% for cuts and waste
- Walls over 4 feet (1.2 m) typically require engineering
- Cap blocks are usually the same count as one row