Volume Calculator

What Is Volume and How Is It Calculated?

Volume is the amount of three-dimensional space that a solid object or shape occupies. While area measures the flat surface inside a two-dimensional shape, volume adds the third dimension — height or depth — to give you a measure of capacity or bulk. Volume is what tells you how much water a tank holds, how many cubic metres of concrete a slab needs, or how much space a shipping box takes up.

Volume is measured in cubic units: cubic metres (m³), cubic feet (ft³), cubic centimetres (cm³), or cubic inches (in³). For liquids, cubic measurements are commonly converted to litres or gallons — which is why this calculator shows results in all four units simultaneously. The formula you use depends entirely on the shape of the object.

Volume Formulas for Every Common 3D Shape

Each three-dimensional shape has its own volume formula. Here are the eight shapes this calculator covers, along with their formulas:

For a box 4m × 3m × 2m: V = 4 × 3 × 2 = 24 m³. For a cylinder with radius 0.5m and height 1.2m: V = π × 0.25 × 1.2 ≈ 0.942 m³ = 942 litres. Enter your own dimensions in the calculator above to get an instant result with formula breakdown and full unit conversions.

Real-World Worked Examples

Example 1 — Concrete for a garden slab

You're pouring a concrete slab that is 4m long, 3m wide, and 100mm (0.1m) thick. Volume = 4 × 3 × 0.1 = 1.2 m³ of concrete. Concrete is ordered by the cubic metre, so you'd order 1.2 m³ — add 5–10% for waste, so realistically 1.3–1.35 m³. At roughly $200–$250 per m³ for ready-mix in Australia, that's around $260–$340 for the pour.

Example 2 — Fish tank capacity

A rectangular fish tank measures 120cm long × 45cm wide × 50cm tall. Convert to metres: 1.2m × 0.45m × 0.5m. Volume = 1.2 × 0.45 × 0.5 = 0.27 m³ = 270 litres. That's your water capacity (less a few centimetres of headroom). Knowing the volume lets you calculate how much dechlorinator, fish food, or filtration capacity you need.

Example 3 — Cylindrical water tank

A round rainwater tank has a diameter of 1.8m (radius = 0.9m) and a height of 2.2m. Volume = π × 0.9² × 2.2 = π × 0.81 × 2.2 ≈ 5.595 m³ = 5,595 litres. That's about 5.6 kilolitres — useful for understanding your water storage capacity and comparing tank sizes.

Volume vs Capacity — What's the Difference?

Volume and capacity are closely related but technically different. Volume refers to the total amount of 3D space a solid occupies — including the material itself. Capacity refers to how much a container can hold inside. For hollow containers like tanks, bowls, and boxes, capacity is the interior volume. For most practical purposes (tanks, pools, aquariums), the two are used interchangeably — the wall thickness is negligible. This calculator computes geometric volume, which is the right figure for most practical applications.

How to Use This Volume Calculator

Click the shape that best matches your object — box or cuboid for anything rectangular, cylinder for round tanks and pipes, sphere for balls and domes, cone for hoppers and funnels, pyramid for tapered structures, capsule for pill-shaped objects, and ellipsoid for egg-shaped forms. Select your input unit from the dropdown (metres, centimetres, feet, or inches), then enter the required dimensions. The calculator instantly shows the volume in your input unit (as cubic units) plus automatic conversions to m³, litres, ft³, and US gallons, with the full working formula displayed below the results.

Volume Unit Conversions — Quick Reference

Volume conversions can be confusing because cubic unit conversions aren't the same as linear ones. 1 metre = 100 centimetres, but 1 m³ = 1,000,000 cm³ (because you cube the linear conversion: 100³ = 1,000,000). Here are the most useful conversions:

• 1 m³ = 1,000 litres = 264.2 US gallons = 35.31 ft³ = 1,000,000 cm³
• 1 ft³ = 28.317 litres = 7.481 US gallons = 0.02832 m³
• 1 litre = 0.001 m³ = 0.0353 ft³ = 0.2642 US gallons = 1,000 cm³
• 1 US gallon = 3.785 litres = 0.003785 m³ = 231 cubic inches

The calculator handles all of these conversions automatically — just enter your dimensions and all four outputs appear at once.

Common Volume Applications by Industry

• Construction and civil engineering: Concrete slabs, footings, retaining walls, trenches, and earthworks are all quoted and ordered by volume in m³. Getting your volume calculation right prevents both shortfalls (costly re-orders) and waste (paying for material you don't need).
• Landscaping and gardening: Mulch, topsoil, compost, and gravel are sold by the cubic metre or cubic yard. Calculate the volume of your garden beds to order the right amount.
• Plumbing and irrigation: Tank and pipe volumes determine flow rates, storage capacity, and pump sizing. A 200-litre hot water cylinder stores very differently from a 400-litre unit, even if they look similar in dimensions.
• Shipping and logistics: Freight is often charged by volumetric weight — the greater of actual weight or calculated volume × a density factor. Knowing your box's volume helps you estimate shipping costs.
• Aquariums and pools: Volume determines the amount of water treatment chemicals, filtration capacity, heater size, and stocking levels for fish. For pools, volume also drives chlorine dosing and pump run times.
• Food and beverage: Baking tins, mixing bowls, storage containers, and fermentation vessels all have volumes that affect recipes, batch sizes, and equipment selection.

Frequently Asked Questions