Gravel Calculator
Area, depth, density, and purchase quantity
Enter the project geometry and supplier material data
Result
Calculation summary
Enter values to see the result
Material layer and order preview
Rectangular gravel layer
How to use this calculator
- 1Choose a rectangular, circular, or known-area project and enter the finished layer depth.
- 2Select a material, then replace the editable density preset with supplier data when available.
- 3Set compaction and waste allowances, choose bulk or bagged purchase, and optionally enter a price basis.
Formula
Order volume = area × depth × (1 + compaction) × (1 + waste); weight = order volume × density
The calculator finds the finished geometric volume, adds separate compaction and waste allowances, then converts volume to weight using the entered bulk density.
Calculation steps
- Validate the plan dimensions or known area, layer depth, density, allowances, and purchase data.
- Convert the plan area to square meters and layer depth to meters.
- Multiply area by depth, then apply compaction and waste allowances in sequence.
- Multiply order volume by the editable bulk density to estimate material weight.
- For bagged material, divide the required weight by bag weight and round up to whole bags.
Worked example
A 5 m × 4 m area at 5 cm depth has a finished volume of 1 m³. With 10% compaction and 5% waste, order volume is 1.155 m³. At 1,600 kg/m³, estimated weight is 1.848 t.
Assumptions
- The layer has uniform depth and the rectangle or circle represents the plan area accurately.
- Compaction allowance represents extra loose material required to achieve the specified finished layer; verify it for the material and equipment.
- Bulk density varies with stone type, gradation, moisture, voids, and compaction. Presets are editable planning examples, not supplier specifications.
- Waste covers handling, grading, spillage, and site irregularity and is applied after the compaction allowance.
- Cost is a simple quantity-times-price estimate and excludes delivery, minimum loads, taxes, labor, equipment, and local pricing rules.
Sources
Frequently asked questions
Should I order gravel by volume or weight?
Use the supplier’s sales unit. This calculator shows both volume and estimated weight so you can compare, but the supplier’s measured quantity and material data govern the order.
Why is material density editable?
The same material name can describe different sizes, gradations, moisture conditions, and void ratios. Supplier bulk density is more reliable than a universal preset.
What does compaction allowance mean?
It adds loose order volume above the finished geometric volume to account for settlement during placement and compaction. It is not a guaranteed shrink factor.
How are bag quantities calculated?
Required material weight is divided by the entered net weight per bag, then rounded up. Confirm that the package weight describes the material itself.
Does the cost include delivery?
No. The optional cost multiplies quantity by the entered price only. Add delivery, minimum order, tax, equipment, and labor separately.