Window Well Gravel Calculator
Estimate drainage gravel for equal window wells using bed dimensions, optional drain-column dimensions, waste, bag volume, density and price.
Default project preview
52 bags
Gravel-bed volume
20 ft³
Drain-column volume
2.8 ft³
Purchased gravel volume
26 ft³
Estimated loose weight
2,553 lb
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.
Gravel-bed length per well
Enter this project assumption in ft. The current imperial default is 4 ft.
Gravel-bed projection or width
Enter this project assumption in ft. The current imperial default is 2.5 ft.
Gravel-bed depth
Enter this project assumption in in. The current imperial default is 6 in.
Number of equal window wells
Enter this project assumption in a unitless value. The current imperial default is 4. Minimum: 1.
Optional drain-column diameter
Enter this project assumption in in. The current imperial default is 8 in. Minimum: 0.
Additional drain-column depth
Enter this project assumption in ft. The current imperial default is 2 ft. Minimum: 0.
Settlement and handling allowance
Enter this project assumption in %. The current imperial default is 12 %. Minimum: 0. Maximum: 50.
Gravel volume per bag
Enter this project assumption in ft³. The current imperial default is 0.5 ft³.
Loose gravel density
Enter this project assumption in lb/ft³. The current imperial default is 100 lb/ft³.
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
Gravel-bed volume
4 equal wells. Default preview: 20 ft³.
Drain-column volume
optional cylindrical gravel column. Default preview: 2.8 ft³.
Purchased gravel volume
0.5 ft³ per bag. Default preview: 26 ft³.
Estimated loose weight
using editable density. Default preview: 2,553 lb.
Unused purchased gravel
full-bag rounding. Default preview: 0.5 ft³.
Gravel cost
bagged gravel only. Default preview: $338.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Volume = rectangular gravel bed + optional cylindrical drain column. Multiply by well count, add settlement allowance and round to full bags.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Window Well Gravel Calculator questions
What is the drain-column input?+
It represents an optional gravel-filled vertical path below the surface bed. Enter zero when the detail does not use one.
Can gravel replace a connected drain?+
Not in every soil or foundation condition. The drainage design must provide a safe path for water away from the opening.
Should the well cover be included?+
No. Covers, drains, liners and excavation are separate items.