Gravel calculator

How to calculate how much gravel you need

This gravel calculator estimates bulk volume, weight and optional material cost for rectangular areas, circular areas and shed bases · Add each separate area with its own depth, then enter the extra-material allowance and supplier density you want to use

Choose the area and depth

For a rectangle, enter length and width · For a circle, enter the diameter across its centre · For a shed base, enter the shed footprint and the margin extending beyond it on each side · Use metres and centimetres in metric mode, or feet, inches and the units shown beside each field in imperial mode

Depth means the thickness of gravel you want after installation · If the base will be compacted, enter its intended finished depth and ask your supplier what additional order allowance is appropriate · The calculator does not select a suitable foundation depth or automatically predict compaction

Volume, allowance and weight

Rectangle area = length × width
Circle area = π × (diameter ÷ 2)²
Volume before extra = sum of each area × its depth
Volume to order = volume before extra × (1 + allowance ÷ 100)
Estimated weight = order volume in m³ × density in kg/m³

Lengths and depths are converted to matching units before multiplication · Results show cubic metres and tonnes in metric mode, or cubic yards and US short tons in imperial mode · One tonne is 1,000 kg · One US short ton is 2,000 lb

The only extra material added is the percentage you enter · The 1,700 kg/m³ starting density is an estimate, not a measured value for your gravel · Ask the supplier for a density consistent with the ordered material and its loose or compacted condition, especially if buying by weight

Worked example: gravel for a shed base

Pad length = shed footprint length + 2 × margin
Pad width = shed footprint width + 2 × margin

An 8 × 10 ft shed with a 1 ft margin on every side needs a 10 × 12 ft pad · At an example finished depth of 4 in, the geometric volume is 40 ft³, about 1.48 yd³ or 1.13 m³ · Entering 10% extra gives about 1.63 yd³ or 1.25 m³ to order · At 1,700 kg/m³, that order is approximately 2.12 tonnes

The example demonstrates quantities and does not specify a suitable foundation for every shed · Confirm excavation, drainage, material type, finished depth and compaction with the shed design and your supplier

Estimate material cost

Choose the supplier’s price unit and enter the price · The tool multiplies the order volume or estimated weight by that price · Delivery and tax are excluded · Check supplier minimum loads and rounding before placing an order