Cubic Meter Calculator: Calculate Volume in 3D Space

What is a cubic meter?

A cubic meter (m³) is the unit of volume in the International System of Units (SI). It is the amount of space inside a cube with sides that are each 1 meter long. This calculator finds the volume of a box-shaped object by multiplying its length, width, and height, all measured in meters.

How to calculate volume in cubic meters

The formula for the volume of a rectangular box (also called a rectangular prism) is:

$\text{Volume (m³)} = \text{Length (m)} \times \text{Width (m)} \times \text{Height (m)}$

Each of the three dimensions must be in meters before they are multiplied. The result is the number of 1-meter cubes that would fit inside the box.

• Length: the longest horizontal side of the box
• Width: the side perpendicular to the length
• Height: the vertical dimension, from bottom to top

For a cube, where every side is the same length, the formula simplifies to:

$\text{Volume (m³)} = \text{Side (m)}^3$

The formula only gives an exact answer for boxes and cubes. For shapes with slanted or curved sides, such as cylinders or cones, a different formula is needed.

How to use the calculator

Enter the length, width, and height in the three input fields. The volume updates as soon as all three values are filled in. The tool accepts values from 0.001 m up to 10,000 m per side; entering 0, a negative number, or a value above that range triggers a warning instead of a result. The copy button copies the volume, in cubic meters, to the clipboard.

Worked example

A room measures 4 m long, 3 m wide, and 2.5 m high.

$4 \times 3 \times 2.5 = 30 \text{ m³}$

The room holds 30 cubic meters of air.

A second example: the interior of a standard 20-foot shipping container is about 5.9 m long, 2.35 m wide, and 2.39 m high.

$5.9 \times 2.35 \times 2.39 \approx 33.1 \text{ m³}$

Converting measurements to meters first

Length, width, and height must all be in meters before they are multiplied. Common conversions:

• 1 foot = 0.3048 m
• 1 inch = 0.0254 m
• 1 centimeter = 0.01 m

For example, a box measuring 10 ft × 12 ft × 8 ft converts to 3.048 m × 3.658 m × 2.438 m, giving a volume of about 27.2 m³. Entering the raw foot or inch values without converting them gives a number in the wrong unit, not cubic meters.

Cubic meters to other volume units

Example: 2.5 m³ × 1,000 = 2,500 liters. Example: 10 m³ × 1.30795 = 13.08 cubic yards.

Where cubic meter calculations are used

Construction: Builders calculate the cubic meters of concrete needed for a slab or footing, and the cubic meters of soil removed during excavation. For an 8 m × 6 m foundation slab that is 0.3 m thick, the volume is 8 × 6 × 0.3 = 14.4 m³ of concrete.

Shipping and freight: Carriers often price cargo by volumetric weight rather than actual weight, especially for bulky, lightweight items. Volumetric weight in kilograms is commonly calculated as the volume in cubic meters divided by 0.006 (equivalent to multiplying by about 166.7).

HVAC and room sizing: Heating and cooling systems are sized partly by the volume of air in a room, measured in cubic meters.

Storage and packaging: Warehouses and shipping companies use cubic meters to plan how much cargo fits in a container or storage space.

Common mistakes

Mixing units. Entering feet or inches directly instead of converting to meters first produces a volume in the wrong unit. A room of 20 ft × 15 ft × 8 ft is not 2,400 m³; converted to meters, it is about 68 m³.

Calculating area instead of volume. Multiplying only length × width gives area in square meters (m²), not volume. Volume needs all three dimensions.

Treating an irregular shape as one rectangle. An L-shaped room is not a single box. It should be split into two or more rectangular sections, each calculated separately, then added together.

Frequently asked questions

How do you calculate cubic meters?

Multiply length, width, and height, all measured in meters. A box that is 2 m × 1.5 m × 0.8 m has a volume of 2.4 m³.

How many liters are in a cubic meter?

Exactly 1,000 liters. One liter equals one cubic decimeter, and there are 1,000 cubic decimeters in a cubic meter.

How do you convert cubic meters to cubic feet?

Multiply the cubic meter value by 35.3147. For example, 33 m³ is about 1,165 cubic feet.

Can I use this calculator if my measurements are in feet or inches?

Convert to meters first, then enter the values. Multiply feet by 0.3048 or inches by 0.0254 to get meters.

What is the difference between square meters and cubic meters?

Square meters (m²) measure a flat area using two dimensions: length and width. Cubic meters (m³) measure the volume of a three-dimensional space using length, width, and height.

Can this calculator handle shapes that are not rectangular?

No. It calculates the volume of a rectangular box only. Irregular shapes need to be split into rectangular sections, each measured and calculated separately, then added together.

How much does a cubic meter of concrete weigh?

Standard concrete weighs roughly 2,400 kg per cubic meter. The exact figure depends on the aggregate mix and moisture content.