How this calculator works
Enter measured project dimensions and planning inputs. The calculator converts them into the quantities shown in the results.
Formula
Gravel volume = trench length × trench width × trench depth, converting inch dimensions to feet. The order volume then applies the selected waste allowance.
Example
For a 40 ft trench that is 12 in wide and 18 in deep, the base trench volume is 60 cu ft before waste.
Assumptions and material notes
The calculator estimates the full rectangular trench volume as gravel. Actual designs may reserve space for pipe, fabric, fittings, or other materials.
Frequently asked questions
Does this account for the drain pipe?
No. It calculates the trench volume from the dimensions entered.
What density should I use?
Use supplier or product density when available; the default is only a planning value.
Can I change waste?
Yes. Enter a project-appropriate waste allowance.
Can I use metric units?
Use the unit choices provided by the calculator fields.
Should I verify quantity?
Yes. Confirm trench dimensions, pipe space, material type, and supplier coverage before ordering.
Related calculators and guide
Gravel Calculators · Gravel Calculator · Gravel Tonnage Calculator · French drain gravel calculation guide
Disclaimer: Estimates are for planning purposes only. Actual material requirements may vary. Verify quantities with your supplier or qualified professional before purchasing or building.