Gravel Base Calculator
Calculate the finished compacted volume for a rectangular base. Enter your supplier’s bulk density if you want a rough weight estimate.
How the calculation works
Compacted cubic feet = length × width × (depth in inches ÷ 12). Divide by 27 for cubic yards. Additional material = compacted volume × (1 + allowance ÷ 100). Optional short tons = adjusted cubic feet × supplied bulk density in lb/ft³ ÷ 2,000.
Worked example
A 20 × 10 ft base at 4 in compacted depth has 66.67 ft³, or 2.47 yd³. At 10% additional material, plan for about 2.72 yd³ before supplier rounding.
Before you order
The extra percentage is a planning allowance, not a guaranteed compaction ratio. Loose-to-compacted volume depends on aggregate, moisture and method. Ask the supplier for density and delivery increments.
Review the calculation method and source notes, then use the supplier checklist before placing an order.
Compacted volume versus delivered material
Length × width × target compacted depth gives the space that the finished base occupies. Delivered loose aggregate may settle when compacted, so the truck or bag quantity may need adjustment. Ask your supplier for the product’s loose-to-compacted factor rather than assuming the extra-percentage input fully accounts for compaction.
The optional short-ton estimate requires a bulk density you enter. Moisture and gradation change actual density; do not use a generic number as a certified truck weight. A 10 × 10 ft area at 4 in compacted depth is 33.33 ft³ before allowance.
Questions before you order
Does this calculate loose delivery volume?
No. The geometric input is target compacted depth. Ask the supplier how much loose material is needed for that compacted result.
Why is the tonnage blank until density is entered?
Aggregate density varies. The tool avoids inventing a weight without your chosen product density.
Can this specify a required base depth?
No. Use the depth from plans or local project guidance.
Continue planning
Content and calculator by pourmeasure. Formula and assumption notes: methodology and sources. Updated October 2026. No independent engineering review is claimed.