Retaining Wall Drainage Stone Calculator
Estimate clean drainage stone behind a retaining wall from wall length, drainage-zone width, average height, waste, density and bag or bulk pricing.
Default project preview
6.11 yd³
Base stone volume
5.56 yd³
Estimated weight
8.56 short tons
Bag count
343
Bulk cost
$415.56
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Retaining wall length
Enter this project assumption in ft. The current imperial default is 50 ft.
Drainage-zone width
Enter this project assumption in in. The current imperial default is 12 in.
Average stone height
Enter this project assumption in ft. The current imperial default is 3 ft.
Settlement and waste allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 75.
Bulk density
Enter this project assumption in short tons/yd³. The current imperial default is 1.4 short tons/yd³.
Bag weight
Enter this project assumption in lb. The current imperial default is 50 lb.
Bulk price
Enter this project assumption in per yd³. The current imperial default is 68 per yd³. Minimum: 0.
Price per bag
Enter this project assumption in a unitless value. The current imperial default is 6.5. Minimum: 0.
How to read the outputs
Base stone volume
before allowance. Default preview: 5.56 yd³.
Estimated weight
entered bulk density. Default preview: 8.56 short tons.
Bag count
50 lb bags. Default preview: 343.
Bulk cost
volume-based supplier price. Default preview: $415.56.
Bagged cost
full bags. Default preview: $2,229.50.
Drainage-zone face
wall length × average height. Default preview: 150 ft².
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Stone volume = wall length × drainage-zone width × average height. Allowance is added before converting volume to weight and full bags.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Retaining Wall Drainage Stone Calculator questions
What stone should be used behind a retaining wall?+
Use the clean, free-draining aggregate specified by the wall-system supplier or project designer.
Does this include the leveling pad?+
No. The calculation covers only the drainage zone entered behind the wall.
Why is density editable?+
Aggregate weight varies by rock type, grading, moisture and void content.