Gravel Calculator: Calculate Gravel, Tons & Coverage
Use this Gravel Calculator to estimate the gravel, crushed stone, pea gravel, river rock, decomposed granite, limestone chippings, slate chippings, or other aggregate needed for a garden bed, path, driveway, patio, shed base, sub-base, or drainage project. Enter the area dimensions, gravel depth, material density, and allowances to calculate cubic yards, cubic metres, US short tons, metric tonnes, bulk bags, small bags, truck loads, and estimated project cost.
How much gravel do you need?
Calculate gravel by multiplying the area by the required gravel depth, then add the selected compaction and spare allowances. For a rectangular area, measure length × width; for a circular area, measure the diameter; for a triangular area, measure the base × height. Enter those measurements in feet (ft), inches (in), metres (m), centimetres (cm), or yards (yd), then enter the gravel depth in inches, millimetres (mm), centimetres, or feet. The calculator converts the measurements into a common volume, calculates cubic yards and cubic metres, and uses the selected gravel density to estimate weight in tons or tonnes.
Gravel Calculator
Area to cover
Gravel type
Membrane & edging
Cost estimate ($)
How the Gravel Calculator Works
The Gravel Calculator calculates the area you want to cover, applies the gravel depth, adds your selected compaction and spare allowance, and converts the required volume into practical ordering quantities. The result can include cubic yards (yd³), cubic metres (m³), US short tons, metric tonnes, bulk bags, small bags, truck deliveries, wheelbarrow loads, weed membrane, edging, pins, and estimated cost.
Measure the Area
Enter the dimensions for a rectangle, circle, or triangle, including length, width, diameter, base, height, and quantity where applicable.
Set Depth and Material
Enter the gravel depth, choose the measurement units, select a gravel or aggregate type, and use the appropriate material density.
Calculate the Order
The calculator converts volume into weight and ordering quantities, then calculates bags, loads, coverage, membrane, edging, and cost from the information supplied.
Gravel Calculator Formula
The basic gravel calculation formula is area × depth = volume. The calculator then applies the selected compaction allowance and spare percentage before converting the final volume into cubic yards, cubic metres, weight, bags, or deliveries.
Length × Width
π × (Diameter ÷ 2)²
½ × Base × Height
Gravel Calculator Example
Consider a rectangular garden area that is 20 ft long × 15 ft wide and needs a 3-inch gravel depth. Select crushed stone with a density of approximately 1.45 US short tons per yd³, then add a 5% spare allowance. The example below shows the complete set of measurements and ordering inputs available in the calculator.
Example Project: Gravel Garden Area
Helpful Information Before Calculating Gravel
Measure the Area Accurately
Take measurements at the actual installation area rather than estimating the overall garden, driveway, path, or patio size. Use the same measurement unit for the length and width within each area.
- Rectangle: measure length and width.
- Circle: measure the full diameter.
- Triangle: measure the base and perpendicular height.
- Multiple areas: add each area separately and enter the quantity for repeated sections.
Choose the Correct Gravel Depth
Gravel depth has a direct effect on the required volume. A decorative gravel bed, garden path, driveway, drainage layer, patio sub-base, and shed base can require different layer thicknesses.
- Enter depth in inches (in) for common shallow gravel layers.
- Use millimetres (mm) or centimetres (cm) for metric specifications.
- Use feet (ft) for deeper aggregate layers.
- Do not confuse gravel depth with the total excavation depth.
Understand Gravel Density
Gravel density determines how much a given volume weighs. Pea gravel, crushed stone, river rock, decomposed granite, limestone chippings, slate chippings, sand, ballast, recycled aggregate, and lightweight lava rock can have different bulk densities.
The calculator uses density in US short tons per cubic yard (t/yd³). Supplier specifications can vary with stone size, grading, moisture content, compaction, and material source, so use the supplier's density when a project requires a more precise tonnage estimate.
Allow for Compaction and Waste
Compaction and spare material serve different purposes. Compaction allowance accounts for aggregate settling or consolidation, while the spare allowance provides additional material for uneven ground, handling losses, trimming, and measurement variation.
- 0%: no additional compaction allowance.
- 20%: compacted material allowance.
- 25%: well-compacted allowance.
- 30%: soft-ground allowance.
- 5% spare: a common additional quantity setting in the calculator.
Convert Volume Into an Order Quantity
Gravel suppliers sell aggregate in different forms. The calculator converts the required volume into the ordering format selected for the project.
- Loose bulk: calculate estimated weight and truck deliveries.
- Bulk bags: calculate whole bags from bag capacity.
- Small bags: calculate individual bags and pallet quantities.
- Wheelbarrow loads: estimate the number of loads from the selected load capacity.
Check Membrane and Edging Requirements
A gravel installation can require weed-control membrane and perimeter edging in addition to the aggregate. The calculator uses your total area and perimeter to estimate these quantities.
- Membrane: calculated from covered area plus the selected overlap percentage.
- Rolls: calculated from the membrane coverage per roll.
- Edging: calculated from the total perimeter.
- Pins: calculated from edging lengths and pins per length.
Use Cost Estimates as Planning Figures
The cost section can estimate gravel, delivery, membrane, edging, spreading, and disposal costs. Gravel can be priced by ton, cubic yard, cubic metre, bag, square foot, or square yard, while delivery can be entered per load and spreading can be entered per square foot.
Enter current supplier or contractor prices for a more useful project estimate. The final purchase price can differ because of minimum order quantities, delivery distance, local supplier pricing, taxes, fuel charges, bag sizes, truck capacity, material availability, and site access.
Keep Units Consistent
The calculator supports feet (ft), inches (in), metres (m), centimetres (cm), and yards (yd) for area dimensions, with inches, millimetres, centimetres, and feet available for gravel depth. Weight can be displayed as US short tons or metric tonnes, while volume is shown in cubic yards (yd³) and cubic metres (m³).
Accurate unit selection prevents large quantity errors. A depth of 3 inches is not the same as 3 feet, and a measurement of 10 metres is not the same as 10 feet.
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