Gravel Calculator

What this gravel calculator returns

Quick answer: Estimate rectangular gravel coverage, cubic feet, cubic yards, short tons, bag count, and optional material cost from area and installed depth.

Measure the finished gravel footprint rather than the excavation as a whole. If a driveway, path, or bed changes width or depth, split it into zones and add the results instead of hiding the variation inside one average.

Formula used by the calculator

Installed cubic feet = length × width × (depth in inches ÷ 12)
Installed cubic yards = cubic feet ÷ 27
Base short tons = cubic yards × density for the same material state
Recommended short tons = base short tons × (1 + stated allowance ÷ 100)

Gravel source basis: unit conversions follow NIST. The USGS aggregates dataset distinguishes construction sand and gravel from crushed stone and reports production by type and end use. Preset densities are editable planning values; use the supplier's value for the selected product and condition. Method and limits.

On the Gravel Calculator, estimated cost equals recommended short tons multiplied by the entered price per ton. Bag count converts recommended tons to pounds, divides by the selected bag weight, and rounds upward. Coverage is length multiplied by width; depth is still required before area becomes volume.

Density is an editable conversion, not a universal constant

The page opens with 1.35 short tons per cubic yard as an example density for gravel. “Gravel” can describe rounded or angular products with different gradations and void space. Moisture, particle size, quarry source, and loose versus compacted condition affect bulk density, so the editable density is more important than the material name alone.

If a supplier provides a different tons-per-yard figure, first confirm whether it describes loose delivered yards or the installed state used by your geometry. Use it directly only when the states match; otherwise obtain a documented yield conversion. Never substitute solid-stone density for bulk aggregate because void space between particles is part of the bulk volume.

Worked gravel example

Example values: 20 ft × 10 ft × (3 in ÷ 12) ÷ 27 = 1.85 yd³. At 1.35 short tons/yd³, base weight is 2.50 short tons; with 10% allowance, the example order is 2.75 short tons. Replace these values with project and supplier data.

Turn the result into an order

Use cubic yards when the yard sells by volume and short tons when it sells by weight. Keep the raw quantity for checking, apply the allowance once, and round only to the supplier's actual increment or full bag count.

Before converting yards to tons, ask whether “gravel” on the quote means rounded gravel, angular crushed gravel, or a named dense-graded base. For a surface that changes from 2 in to 4 in, create two measured zones instead of averaging the depth; then attach the product and density to each zone. Use the driveway calculator when the job has distinct structural courses.

Common gravel estimating errors

• Entering excavation depth instead of the intended finished gravel layer.
• Using a generic density after the supplier has provided a product value.
• Adding compaction and waste as overlapping percentages without defining what each covers.

Questions specific to gravel