Calculated
Gravel Calculator
Sign up to favourite this calculatorEnter the area, finished depth and material density to estimate the gravel volume, weight, order quantity and cost for a driveway, path or landscaping project.
Your gravel estimate
Driveway — net area 40.00 m² at 50 mm finished depth, with a 5.0% allowance.
Estimated order quantity
Net area
40.00 m²Order volume
2.100 m³Estimated mass
3.36 t3.70 US tn · 3.31 UK tnDensity entered directly — use loose or compacted bulk density from your supplier where available.
Area and volume
| Item | Value |
|---|---|
| Total area | 40.00 m² |
| Excluded area | 0 m² |
| Net area | 40.00 m² |
| Finished depth | 50 mm |
| Finished volume | 2.000 m³ |
| Extra material allowance | 5.0% |
| Order volume (with allowance) | 2.100 m³ |
| Order volume in litres | 2,100 L |
Weight equivalents
| Unit | Value |
|---|---|
| Required mass before rounding | 3,360 kg |
| Metric tonnes | 3.360 t |
| US short tons | 3.704 US tn |
| UK long tons | 3.307 UK tn |
| Pounds | 7,408 lb |
Your order
| Item | Value |
|---|---|
| Order format | Loose, weighed in bulk |
| Required before rounding | 3.360 tonnes |
| Rounding increment | 0.100 tonnes |
| Rounded order quantity | 3.4 tonnes |
| Extra after rounding | 0.040 tonnes |
Estimated cost
| Item | Value |
|---|
Check the area to exclude
This is an order-planning estimate only. It does not recommend a material, aggregate type or depth, calculate structural suitability, drainage or foundation requirements, quote delivery or stock, or estimate excavation or installation. For those, check your supplier's product data or consult a qualified professional.
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Assumptions and limits
- An estimate from the numbers you entered, for guidance only. It is not financial, tax or medical advice.
- Calculator version 1, last updated 25 October 2026.
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How to use this calculator
- Choose Metric or Imperial units, and a rectangle or circle shape.
- Enter the dimensions, and any area to exclude such as a planting bed.
- Enter your finished gravel depth.
- Enter your supplier's density, or choose an approximate material preset as a starting point.
- Set an allowance for compaction, uneven ground and handling.
- Choose how you plan to order — loose by weight, in bags, or loose by volume — and add a price if you want a cost estimate.
- The calculator estimates the order quantity, weight and cost.
What do I need to enter?
- Project — a label for your reference only. It does not change the result.
- Measurement units — Metric (metres, millimetres) or Imperial (feet, inches). Switching converts what you have typed.
- Shape — Rectangle takes a length and width; Circle takes a diameter. Dimensions must be greater than zero.
- Area to exclude (optional) — one total for planting beds or hardstanding inside the shape. It must be smaller than the total area.
- Finished depth — how deep the laid gravel will be, in mm or inches, not the depth of any excavation.
- Density source, Material and Density value — enter your supplier's density, or pick a material preset that fills in an approximate value you can still edit. Choose the density unit from the dropdown.
- Extra material allowance — 0% to 30% added to the volume for compaction, settlement and handling losses.
- Order format — Loose, weighed in bulk (rounded up to a tonne increment); Bags (you give the bag weight); or Loose, sold by volume (rounded up to a volume increment).
- Cost (optional) — choose Add material cost to enter a currency, a price per order unit and an allowance for other materials.
What do the results show?
- Estimated order quantity — the main figure: tonnes (US short tons in Imperial), bags or volume, rounded up to your chosen increment.
- Net area, Order volume andEstimated mass — the area covered, the volume including your allowance, and the weight in metric tonnes with US and UK ton equivalents.
- Area and volume — a table from total area through to the order volume.
- Weight equivalents — the mass before rounding in tonnes, US short tons, UK long tons and pounds.
- Your order — how the quantity was rounded, and any extra bought as a result.
- Estimated cost — shown when cost is switched on: the rounded quantity multiplied by your price, plus other materials.
How is gravel quantity calculated?
The calculator finds the net area to cover, multiplies it by the finished depth to get a volume, adds your chosen allowance, then multiplies by the material density to get a mass. That mass is then rounded up to a practical order quantity in whichever format you choose.
finished volume = net area × finished depth
- net area = gross area − excluded area
- order volume = finished volume × (1 + allowance ÷ 100)
- required mass = order volume × density
Example: a 10 m × 4 m area, 50 mm deep, at 1.6 t/m³ density, 5% allowance
- 10 × 4 = 40 m² net area.
- 50 mm is 0.05 m, so 40 × 0.05 = 2 m³ finished volume.
- With a 5% allowance, 2 × 1.05 = 2.1 m³ order volume.
- 2.1 m³ × 1,600 kg/m³ = 3,360 kg, or 3.36 tonnes, before rounding.
- Rounded up to the nearest 0.1 tonnes, that is 3.4 tonnes to order.
Metric and imperial gravel measurements
Every measurement is converted into a single internal volume in cubic metres and a single internal mass in kilograms before any arithmetic happens, so the metric and imperial results can never disagree. Imperial mode uses feet for length, inches for depth, square feet for area and cubic yards for loose volume.
Choosing a gravel density
Density is the figure that turns a volume into a weight, and it varies by material, particle size, moisture content and how compacted the material is. Where your supplier states a loose or compacted bulk density for the specific product you are buying, use that. The material presets in this calculator — decorative gravel or shingle, pea gravel, crushed stone or gravel, crushed limestone or granite, road base and sand — are approximate starting points around 1.5 to 1.9 tonnes per cubic metre, not a substitute for your supplier's own figures.
Metric tonnes, US short tons and UK long tons
"Ton" means different things in different places, so this calculator always shows a weight alongside its exact unit rather than an unqualified "ton".
| Unit | Exact weight |
|---|---|
| Metric tonne | 1,000 kg |
| US short ton | 907.18474 kg (2,000 lb) |
| UK long ton (Imperial ton) | 1,016.0469088 kg (2,240 lb) |
What this calculator does not cover
This is an order-planning estimate only. It does not recommend a gravel or aggregate type, suggest a finished depth, calculate structural suitability, drainage or foundation requirements, quote delivery or stock availability, or estimate excavation or installation. Ground conditions, compaction, drainage, edging, geotextile membranes and structural base design can all change what a real project needs — check your supplier's product data and installation requirements, or consult a qualified professional, before ordering or building.
Related tools
Pouring a concrete slab or path on top of this sub-base? See the Concrete Volume Calculator.
Frequently asked questions
How do I calculate how much gravel I need?
Multiply the area to cover by the finished depth to get the volume, add an allowance for compaction and handling, then multiply by the density of your chosen material to get the weight. This calculator does the conversion for you and rounds up to a practical order quantity.
How many tonnes of gravel do I need?
Work out the volume in cubic metres (area × depth), add your allowance, then multiply by the density in tonnes per cubic metre. A typical gravel around 1.6 t/m³ needs roughly 1.6 tonnes per cubic metre of order volume — always check the density stated for your specific product.
How much extra should I allow for gravel?
A common starting point is 5% to 10% on top of the calculated volume, to cover compaction, settling, uneven ground and handling losses. This calculator lets you set any allowance from 0% to 30% — it is a buffer you choose, not a fixed rule.
What density should I use for gravel?
Use the loose or compacted bulk density stated by your supplier for the specific product where it is available — density varies with material, particle size, moisture and compaction. The presets in this calculator (around 1.5 to 1.9 t/m³ for common gravels, sand and road base) are approximate starting points, not a substitute for your supplier's figures.
What is the difference between a UK ton and a US ton?
A metric tonne is 1,000 kg. A US short ton is 907.18474 kg (2,000 lb) and a UK long ton — sometimes called an Imperial ton — is 1,016.0469088 kg (2,240 lb). These are three different weights, so this calculator always shows them separately rather than using an unqualified "ton".
How many bulk bags of gravel do I need?
Enter the actual weight stated on your chosen bag — bulk bags vary and not every one holds exactly one tonne. The calculator divides your required mass by that bag weight and rounds up to a whole number of bags.
Does this work for a sloped or uneven area?
The calculator assumes a consistent finished depth over a flat area. A sloped or uneven area needs more gravel to reach the same finished depth throughout — measure an average depth if the ground varies, or break an irregular area into simpler shapes and add the results together, and add a larger allowance to cover the extra material.
What depth of gravel should I use, and which aggregate is best?
This calculator estimates quantity from the depth and material you choose — it does not recommend a depth or an aggregate type for your project. The right depth and material depend on the intended use, sub-base, drainage and local ground conditions; check product guidance or a qualified professional for those decisions.
Does this include delivery or labour costs?
No. The optional cost estimate covers only the material price you enter, multiplied by the rounded order quantity, plus any other material allowance you add. It excludes delivery charges, tax, labour, excavation, plant hire and anything else not entered.
Last updated 25 October 2026.