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Gravel Calculator — Bags vs Bulk Delivery
Estimate material for a rectangular gravel area, then compare small bags with a bulk delivery quote. See cubic yards, cubic metres, metric tonnes and US short tons together.
Density is an editable example, not a universal gravel value. Use your supplier’s bulk density for the condition you are measuring. This is a quantity estimate, not a driveway-base design.
How gravel quantity is calculated
Volume equals length × width × depth, using consistent units. The calculator adds your ordering allowance, then multiplies volume by the density you enter. Whole bags are rounded up. Bulk cost uses the larger of required weight and the supplier’s minimum billed weight, plus delivery.
Worked example: 5 × 3 metres at 5 centimetres needs 0.75 m³ before allowance. Adding 10% gives 0.825 m³. At an assumed 1,600 kg/m³, that is 1,320 kg, or 53 bags of 25 kg. With the example prices, bags cost 265 and bulk costs 135.80 in the selected currency.
Are tonnes and tons the same?
No. A metric tonne is 1,000 kg; a US short ton is 2,000 lb, approximately 907.185 kg. This tool labels both explicitly. It does not use the British long ton.
Does the allowance calculate compaction?
No. The percentage is an ordering allowance you choose. Loose and compacted materials have different bulk densities. Ask your supplier for a density and allowance that match the depth and condition you need, and avoid double-counting compaction.
Why not use the weight of solid stone?
Bulk density includes voids between particles and depends on grading, moisture and packing. A solid-rock density can substantially overestimate a loose gravel order.
Sources and assumptions
Dimensional estimate reference: Cemex UK aggregate calculator. The 1,600 kg/m³ default is only an illustrative input; confirm your material’s density with its supplier. Prices are examples. Reviewed 30 October 2026. Calculations run in your browser; this calculator does not send your entered measurements to a server.
River rock and pea gravel calculator
For a rectangular river rock bed or pea gravel area, enter its length, width and intended material depth above. Volume is calculated first; weight depends on the supplier bulk density you enter. The example density is not a preset for either stone type.
How many bags of river rock do I need?
Use the package weight and supplier bulk density to estimate whole bags. If a package states volume coverage instead, divide your required volume by that coverage using matching units. Stone size, void spaces and moisture affect coverage; confirm the product information before ordering.
Using this as a gravel driveway calculator
Estimate each material layer separately using its own dimensions and supplier density. The ordering allowance adds a percentage to volume; it does not calculate a compaction factor or specify a suitable driveway base depth.
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