How to calculate gravel for a driveway
A driveway gravel estimate needs length, width and compacted/planned depth. Those dimensions produce a volume; an assumed material density then converts the volume into an estimated weight for ordering.
Depth matters as much as driveway area
A long driveway with a shallow top layer can use less material than a smaller area with a deep base. Enter the depth for the specific layer you are estimating rather than treating the result as a complete driveway design.
Density changes the tonnage
Different aggregates do not weigh exactly the same per cubic yard. The density field is editable so the estimate can be aligned with the supplier’s material.
Compaction and delivery are separate considerations
The calculator estimates quantity. Real ordering may also need to consider compaction, truck capacity, minimum delivery quantities and how easily material can be placed on site.
That footprint contains about 7.78 yd³. At 1.4 tons/yd³ it is about 10.89 tons before allowance, or about 11.98 tons with a 10% allowance.