Retaining Wall Block Calculator
Enter your wall's length and height along with your block's face dimensions to calculate the number of courses and total blocks needed.
How the Retaining Wall Block formula works
Courses stacked to reach wall height, times blocks per course:
Courses = ceil(Wall height × 12 / Block face height) Blocks per course = ceil(Wall length × 12 / Block face length) Total blocks = Courses × Blocks per course
Step-by-step calculation
- Divide wall height by a single block's face height to find the number of courses (rows) needed, rounding up.
- Divide wall length by a single block's face length to find blocks per course, rounding up.
- Multiply courses by blocks per course for the total block count.
Worked example
A wall 24 ft long and 3 ft high, using blocks with a 6-inch face height and 16-inch face length: Courses = ceil(36/6) = 6. Blocks per course = ceil(288/16) = 18. Total blocks = 6 × 18 = 108.
Frequently asked questions
Does this account for base or capstone blocks?
No — this calculates the main wall face blocks only. Base course preparation and capstones are typically ordered separately, often as different product lines from the same manufacturer.
Do retaining walls need special engineering for height?
Taller retaining walls (commonly above about 3-4 feet) often require engineering review and permits due to the soil pressure involved — check local building code requirements before building a tall wall.