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Gravel Calculator
Calculate compacted gravel volume, estimated mass, load count, delivered unit cost, and layer coverage. The dedicated section diagram labels length, width, compacted depth, density conversion, and truck rounding.
Compacted volume-
Estimated material mass-
Eight-tonne loads-
Estimated material cost-
Decision view
Compacted gravel layer and delivery conversion
Compacted gravel layer and delivery conversionLength, width, and compacted depth form the finished prism before bulk density converts volume to tonnes and nominal loads.
Exact scenario comparisonCompacted depth (cm) changes while all other entered assumptions remain constant.
| Compacted depth (cm) | Compacted volume | Estimated material mass | Eight-tonne loads | Estimated material cost |
|---|
How to use Gravel Calculator
- Measure the finished length and average width, then select the specified compacted layer depth.
- Use a supplier density for the exact aggregate and confirm whether that density represents loose or compacted material.
- Apply a separate compaction, irregular-shape, and delivery allowance when the supplier's quoted tonnage basis requires it.
Calculator guide
Understanding Gravel Calculator
Gravel is designed by compacted geometry but commonly sold by mass or truckload. This calculator connects the finished layer dimensions to cubic metres, tonnes, nominal eight-tonne loads, and material cost.
Calculation method
How the calculation works
Multiply length, width, and converted depth for compacted volume, then apply bulk density and unit price. Convert depth from centimetres to metres, multiply length by width and depth for compacted volume, multiply by bulk density for tonnes, and round the nominal eight-tonne load count upward.
Order control
Loose delivery and compacted finish are not the same volume
Aggregate particles rearrange under compaction, reducing voids and finished thickness.
Worked situations
Practical examples
- A 12 m by 4 m layer at 10 cm compacted depth occupies 4.8 m3.
- At 1.65 t/m3, the geometric requirement corresponds to about 7.92 tonnes.
- The nominal truck indicator rounds that mass to one eight-tonne load, but legal payload and supplier dispatch rules control delivery.
Better inputs
Useful tips
- Measure depth after compaction; loose placed depth must usually be greater.
- Use average width only for reasonably regular areas, or split curves and tapers into smaller shapes.
- Confirm minimum order, delivery charge, access, vehicle size, and whether the supplier sells by tonne or cubic metre.
Before relying on the result
Limitations and common mistakes
- The model does not automatically increase loose volume for compaction, settlement, contamination, or subgrade loss.
- Bulk density changes with aggregate grading, rock type, moisture, voids, and how the load is measured.
- Drainage design, geotextile, excavation, base preparation, edge restraint, and structural suitability are excluded.
Reference
Key terms
- Compacted depth
- Finished thickness after the aggregate has been placed and densified.
- Bulk density
- Mass of aggregate per bulk volume, including void space between particles.
- Subgrade
- Prepared soil or existing material supporting the aggregate layers.
- Payload
- Material mass a delivery vehicle can legally and safely carry.
Important note
Calculated from the entered measurements and stated coverage or quantity rules. Confirm field dimensions, waste, product requirements, structural conditions, and local codes before purchasing or building.
Frequently asked questions
Should I enter loose or compacted depth?
Enter the required finished compacted depth. Then apply the supplier or engineer's conversion to determine loose delivery quantity.
Why does the calculator use density?
Geometry produces volume, while many quarries and haulers invoice by mass.
Is one calculated load always one truck?
No. The eight-tonne figure is a planning reference; legal payload, truck type, access, and supplier routing vary.
Does cost include delivery?
Only if the entered price per tonne already includes delivery and related charges.