Free tool
French Drain Calculator
Enter your trench size and get gravel, pipe, fabric and soil quantities, plus the slope you need.
Four quick steps.
- 1
Set the trench
Length, width and depth.
- 2
Choose the pipe
Pipe diameter and wrapped or unwrapped fabric.
- 3
See the quantities
Gravel tons, pipe feet, fabric and soil to haul.
- 4
Check the slope
The fall you need along the run.
About this tool.
How much gravel per foot?
It depends on trench size. A 10 inch by 18 inch trench uses roughly a cubic foot of stone per linear foot.
Do I need fabric?
Almost always. It keeps soil out of the stone and keeps the drain working.
Is a DIY drain a good idea?
Possibly for short runs. Slope and outlet are critical, so ask us if you are unsure.
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