How to use this retaining wall block calculator
Block count depends on visible wall height, course height and nominal block length. This planner estimates a straight wall made of uniform blocks. It cannot design soil reinforcement, drainage performance or an engineered wall.
Step-by-step instructions
- Measure the intended visible wall length and height.
- Choose the actual manufacturer block dimensions.
- Set base trench dimensions and waste percentage.
Calculation formula
Important assumptions and limitations
Straight wall, level courses and nominal block dimensions. Buried courses, caps, setbacks, drainage and reinforcement are not included in the main block total.
For material orders, confirm package yields, stock sizes and installation instructions with the actual manufacturer or supplier. Your building department determines the applicable local code; a quantity estimator is not a structural design or permit approval.
Frequently asked questions
Can this calculate a four-foot retaining wall design?
No. Retaining walls can pose collapse hazards. Height limits and engineering requirements vary; consult the manufacturer and local building department.
Why does my wall need drainage?
Water pressure behind a retaining wall can cause failure. The appropriate drain design needs a site-specific assessment.
We publish formulas and assumptions so you can verify an estimate. Learn about our methodology or report an issue.