Landscape wall planning
Retaining Wall Block Calculator
Estimate the blocks, caps, base gravel, drainage rock, landscape fabric, optional geogrid, and rough material cost for a small retaining wall or raised landscape wall.
How to use the retaining wall block calculator
Enter the finished wall length and exposed height, then match the block dimensions to the product you plan to buy. The calculator estimates full courses, block counts with waste, cap blocks, compacted base gravel, drainage rock behind the wall, fabric, and a planning geogrid quantity.
For shopping, round up to full pallets, full bags, or delivery minimums. For building, follow the manufacturer’s directions for base depth, buried courses, setbacks, drainage pipe, geogrid placement, and maximum wall height.
Retaining wall material formulas
- Courses: wall height in inches ÷ block height, rounded up.
- Blocks per course: wall length in inches ÷ block face length, rounded up.
- Base gravel: wall length × trench width × compacted depth.
- Drainage rock: wall length × drainage thickness × wall height.
- Geogrid: estimated layers × wall length × reinforcement length behind the wall.
Retaining wall FAQ
How many retaining wall blocks are on a pallet?
It depends on the block size and manufacturer. Once this calculator gives you a block count, divide by the blocks per pallet listed by the store or manufacturer and round up.
Should I include buried blocks?
Many walls bury part or all of the first course. If you want that included in the block count, add the buried height to the wall height before calculating.
How deep should the gravel base be?
Small landscape walls often use several inches of compacted gravel base, but the right depth depends on wall height, soil, drainage, frost, and the block system. Use the block maker’s guide as the final rule.
Do I need drainage pipe?
Many retaining walls need drainage behind the wall so water pressure does not build up. Taller walls, clay soils, slopes, and wet areas deserve extra drainage planning.