French Drain Gravel Calculator
Calculation Formula
Total Stone Needed (Rectangle) = (Length * Width * Depth) / 27
Total Stone Needed (Circle) = (π * Radius² * Depth) / 27
Total Weight = Total Stone Needed * weightFactor
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Total Stone Needed (Rectangle) = (Length * Width * Depth) / 27
Total Stone Needed (Circle) = (π * Radius² * Depth) / 27
Total Weight = Total Stone Needed * weightFactor
Firstly, please enter the specific length of the french drain you plan to install.
Next, enter the width of the french drain. In most installation scenarios, a width of 8 to 12 inches is sufficient.
Then, enter the depth of the french drain. Generally, a standard depth of about 12 inches will ensure there is approximately 5 inches of gravel and 3 inches of topsoil or grass above a 4-inch drainage pipe.
If your french drain area has protrusions or slope changes, you may need to increase the depth accordingly to ensure a consistent slope along the entire length of the drainage ditch.
Lastly, enter the outer diameter of the drainage pipe installed in the trench and click the calculate button. For most residential applications, a 4-inch perforated PVC pipe is sufficient, with an actual outer diameter of 4.215 inches.
Please note that the calculated amount of soil to be removed does not include the top 3 inches of grass/soil layer, as this layer is typically replaced on top of the drainage ditch.
Additionally, please note that the calculated soil removal volume has already considered a 30% expansion coefficient, which is the amount of expansion that soil typically undergoes when it is dug out from a compressed state.