Driveways compact — order for it
A gravel driveway loses 20–30% of its loose depth to compaction and sinking in year one, so the working rule is order 4 inches to end up with 3. The calculator gives the tonnage at your entered depth; add the compaction margin on top when you call the quarry.
The three-layer driveway
Long-lasting driveways use a big base stone (item #4 or breaker run) under #57 crusher run, crowned in the middle so water sheds to the edges. Resurfacing annually with a thin layer of #57 is cheaper than rebuilding a muddy base — budget for a fresh yard or two every couple of years.
Sources and standards
Where these figures come from
Every formula on this page is implemented from the published reference material below. Where a value depends on a regional code, the calculator lets you override it rather than assuming one jurisdiction.
- ASTM International — C94 for ready-mixed concrete, C150 for cement and C143 for slump testing.
- American Concrete Institute — ACI 318 code requirements and ACI 302 slab construction guidance.
- Portland Cement Association — mix design, yield and curing data published by the US cement industry.
Figures, formulas and reference tables last verified: 19 September 2026.