How much gravel do I need?

Quick answer

For a rectangular gravel area, cubic yards = length (ft) × width (ft) × depth (in) ÷ 324. To estimate tons, multiply cubic yards by the gravel density in tons per cubic yard. Because density varies by material and moisture, use the supplier’s density when available.

For example, a 50 ft × 12 ft driveway at 4 in deep is about 7.41 cubic yards before waste or compaction allowance. If the chosen aggregate is 1.5 tons per cubic yard, that is about 11.11 tons before order rounding.

Gravel formula

Start with the finished dimensions of the area you actually want to cover.

1. Area in square feet: length × width.
2. Volume in cubic feet: area × depth in feet.
3. Cubic yards: cubic feet ÷ 27.
4. Tons: cubic yards × material density.

A shortcut when depth is entered in inches is length × width × depth ÷ 324. That produces cubic yards directly.

What depth should I use?

The correct finished depth depends on the project, base conditions and aggregate. A decorative landscape layer may be shallower than a driveway base. Do not assume one universal depth for every project.

Cubic yards vs tons

Cubic yards measure volume. Tons measure weight. Two gravel products can occupy the same volume but weigh different amounts because particle size, composition, moisture and compaction differ.

That is why a calculator should treat density as an input or material assumption rather than pretending one ton-per-yard value is exact for every aggregate. AcreSketch includes planning density presets, but the supplier’s actual figure should override them when you are placing an order.

How much extra gravel should I order?

Real projects rarely match the neat mathematical volume exactly. Excavation variation, compaction, uneven grade, spillage and supplier order increments can all change the quantity. A modest waste/compaction allowance is common for planning, but the correct buffer depends on the job.

After calculating the raw quantity, round to the supplier’s practical order increment. For example, if the calculation gives 10.6 tons and the supplier sells in half-ton increments, the planning order would usually round upward rather than downward.

Worked example: driveway gravel

Suppose a driveway is 60 ft long and 10 ft wide, and the intended gravel layer is 3 in deep.

• Area = 60 × 10 = 600 sq ft
• Cubic yards = 60 × 10 × 3 ÷ 324 = 5.56 yd³
• At 1.5 tons/yd³ = 8.33 tons
• With a 10% planning allowance = about 9.17 tons

This is an estimate, not a supplier specification. Confirm the selected aggregate’s density and the site’s required compacted depth before ordering.

Common mistakes that cause bad gravel estimates

• Entering depth in inches but treating it as feet.
• Using total lot area instead of the actual driveway or path area.
• Forgetting to subtract sections that will not receive gravel.
• Using one generic density for every material.
• Ignoring multiple layers in a driveway build-up.
• Rounding down to save money and then running short.

Frequently asked questions