How the gravel estimate is calculated.
The planner separates geometry, material assumptions and supplier rules so you can see why the amount purchased can be higher than the theoretical volume.
1. Installed volume
installed cubic yards = installed cubic feet ÷ 27
When multiple areas use different depths, each area is calculated separately and the volumes are added.
2. Loose quantity and weight
exact tons = loose yd³ × density (tons/yd³)
Density varies with material, gradation, moisture and supplier. The presets are planning values only; use a supplier-provided bulk density when available.
3. Supplier order
order tons = base order rounded upward to the supplier increment
This is why the displayed order can exceed the physical planning need. The planner shows both values instead of hiding the difference.
4. Bag comparison
The comparison uses the bag volume and price you enter. It does not assume live store prices.
5. Reverse coverage
The “I already have gravel” mode reverses the conversion from tons, cubic yards or bags into loose volume, removes the entered allowances, and divides by target depth to estimate coverage.
6. Budget mode
The budget mode first subtracts delivery, then finds the largest supplier-order increment affordable within the entered budget, subject to the entered minimum load. It then converts that order back into approximate installed coverage.
7. Supplier quote comparison
Each quote can be entered per ton or per cubic yard. Both are normalized through the same project quantity and editable material density. Each supplier's own minimum, increment and delivery charge is applied before comparing delivered totals.
Important limits
The planner does not determine structural depth, drainage design, excavation, geotextile, grading, labor, equipment, taxes, access surcharges or suitability of a specific aggregate. Verify the final order, product, pricing and delivery terms with the supplier.
Method version: 1.1 · September 2026.
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