French Drain Gravel Calculator
Estimate clean drainage-gravel volume, weight, bags and material cost for a French drain after subtracting pipe displacement.
Default project preview
7.18 yd³
Equivalent bags
402
Gross trench volume
6.67 yd³
Pipe displacement
0.259 yd³
Net gravel volume
6.41 yd³
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Net gravel volume = trench volume − pipe-cylinder volume. Order volume adds allowance; weight uses entered bulk density.
FAQ
French Drain Gravel Calculator questions
Why subtract the pipe volume?+
The pipe occupies part of the gravel envelope, reducing the aggregate volume slightly.
Should the entire trench be filled with gravel?+
Not always. The design may include soil cover, fabric folds or another surface layer.
Why can delivered weight differ?+
Moisture, gradation, compaction and supplier density change actual weight per volume.