Gravel Calculator
Estimate gravel volume and optional mass using your supplier's density and order size.
This tool runs entirely in your browser. Your data is never uploaded, never stored, and never leaves your device.
Estimate multi-bed gravel volume, or use a supplier-specific bulk density to calculate weight and whole ordering increments without assuming a universal density.
How to use it
- 1Measure each rectangular bed, its excluded area and its uniform layer depth.
- 2Choose volume only or enter supplier bulk density and a weight ordering increment.
- 3Apply your own allowance and review volumes, explicitly labelled weight units and surplus.
- 4Download the bed-by-bed JSON estimate.
Example
- Input
- 0.6 m³ base volume, 10% allowance, supplied 1,600 kg/m³ density and 25 kg increments.
- Output
- 0.66 m³; 1,056 kg required; 43 increments = 1,075 kg; 19 kg rounding surplus.
The density is an illustrative user input, not a default gravel property.
What happens to your data
Bed measurements and supplier settings remain in the browser; no input is uploaded or saved. Your optional download includes the active settings and estimate assumptions.
Last updated October 2026
Gravel volume comes from the space you need to fill; its weight also depends on the aggregate and its condition. This gravel calculator keeps those two questions separate. Add rectangular beds with their own depths and excluded areas, then calculate combined volume. If your supplier provides an appropriate bulk density, you can additionally estimate weight and round to their bag or delivery increment.
There is no silently chosen gravel density, compaction percentage or universal tonne-bag size. Volume-only mode works without any density input. Weight mode exposes the density, ordering increment and resulting surplus so the estimate can be checked against the actual supplier specification.
How it works
Each bed contributes (length × width − excluded area) × uniform layer depth. Metric beds use metres for sides and millimetres for depth; US beds use feet and inches. The calculator adds bed volumes before applying your single extra allowance, then displays cubic metres, cubic feet and cubic yards. One cubic yard is exactly 27 cubic feet. No hidden conversion or rounding to whole yards is applied.
For a weight order, required volume in m³ is multiplied by supplier bulk density in kg/m³. US mode accepts lb/ft³ and converts using the defined foot and pound relationships. This must be bulk density for the selected material and matching condition, not the density of a solid piece of rock. Moisture, particle distribution, packing and compaction can affect the mass occupying a volume. A percentage you enter is only an explicit quantity allowance; it is not a geotechnical compaction model.
Divide estimated mass by your chosen order increment, round up, then multiply back to obtain purchase mass. For example, an increment can represent a stated bag weight, or a supplier's permitted bulk delivery step. It does not establish a lorry payload, minimum order or safe transport load. The report identifies metric tonnes as 1,000 kg and US short tons as 2,000 lb instead of using the ambiguous word ton alone.
Only uniform rectangular layers are represented. For sloped or irregular areas, divide the measured project into appropriate separate sections or obtain a professional takeoff. Required depth, drainage suitability, structural loading and foundation design are outside this tool. Decimal arithmetic protects order-rounding boundaries, while the physical estimate still depends on the measurements and density you supply.
Worked example: Two beds with a supplied density and mass increment
- Input
- 4 × 2 m at 50 mm, plus 2 × 1 m at 100 mm; 10% allowance; supplied density 1,600 kg/m³; order increments of 25 kg.
- Result
- 0.6 m³ base; 0.66 m³ required; 1,056 kg estimated; 43 increments = 1,075 kg purchased; 19 kg rounding surplus.
Density and allowance are example inputs, not universal properties of gravel. Confirm your product and condition.
Common use cases
- Add several landscape beds with different depths before obtaining a single volume estimate.
- Request a supplier quote in m³ or yd³ without inventing a material density.
- Convert measured volume to weight using the supplier's specific bulk density and delivery increment.
- Compare whole-bag and bulk weight increments while seeing their separate rounding surplus.
Frequently asked questions
How much gravel do I need?＋
Start with net area × layer depth for every bed, then add the volumes. A 4 × 2 m bed at 50 mm needs 0.4 m³ before allowance. A second 2 × 1 m bed at 100 mm adds 0.2 m³, making 0.6 m³ total.
Why must I enter a density for tonnes?＋
Volume alone cannot determine weight. Use bulk density from the supplier for that aggregate and the relevant loose/compacted/moisture state. The calculator deliberately has no universal default. If you cannot obtain an appropriate value, use volume-only mode and ask the supplier to confirm tonnage.
Is a tonne the same as a ton?＋
Not necessarily. Here metric tonnes are 1,000 kg and US short tons are 2,000 lb. Both are labelled explicitly. If a supplier quotes another unit or a loosely described bulk bag, confirm its stated mass before entering your order increment.
Does the allowance include compaction?＋
Only if you deliberately enter an allowance supported by your project and product guidance. The tool does not prescribe a compaction rate. Ensure the depth and bulk density refer to compatible conditions; multiplying a compacted depth by an unrelated loose density can mislead.
Can it tell me driveway or foundation depth?＋
No. It estimates quantities from a supplied depth and does not assess soil, traffic, drainage, loading or local requirements. Product selection and structural layers need appropriate manufacturer or professional guidance.
Can I save the bed breakdown?＋
Download the local JSON estimate, which includes active dimensions, each bed's net area and volume, allowance, ordering assumptions and any entered density. Inputs are not uploaded or persisted by this workflow, and edits remove stale results.
Related tools
Mulch Calculator
Estimate top-up mulch for multiple beds and compare whole bags with bulk volume.
Concrete Calculator
Estimate slab or cylinder concrete volume and whole bags using your product yield and allowance.
Volume Calculator
Calculate mixed-unit shapes and partly filled tanks, with diameter input and a CSV calculation.
Unit Converter
Convert length, weight and temperature — mm to inches, kg to pounds, Celsius to Fahrenheit.