How do I calculate cubic feet from inches?

To calculate cubic feet from inches, divide each dimension by 12 to convert to feet, then multiply the three converted values together. For example, a box 24 inches long by 18 inches wide by 12 inches tall is 2 ft x 1.5 ft x 1 ft = 3 cubic feet. Alternatively, multiply the three inch measurements together to get cubic inches, then divide by 1,728 (because 1 cubic foot = 12 x 12 x 12 = 1,728 cubic inches).

How many cubic feet are in a cubic metre?

One cubic metre equals approximately 35.3147 cubic feet. Conversely, one cubic foot equals approximately 0.028317 cubic metres. This conversion is useful when dealing with shipping containers, concrete pours, and building materials where metric and imperial measurements are both in use. To convert cubic feet to cubic metres, multiply by 0.028317. To convert cubic metres to cubic feet, multiply by 35.3147.

What is the difference between cubic feet and square feet?

Square feet measure a two-dimensional area (length x width), while cubic feet measure a three-dimensional volume (length x width x height). Square feet are used for floor areas and surface areas. Cubic feet are used to measure the volume of a space or container, such as a room's air volume, a skip bin's capacity, or a concrete pour. You can convert from square feet to cubic feet by multiplying by the third dimension (height or depth) in feet.

Cubic Feet Calculator

This calculator works out the volume of a rectangular space or object in cubic feet, the standard unit for sizing storage units, skip bins, shipping crates, air conditioning loads and concrete or aquarium volumes. You enter the length, width and height of the space, choosing your input unit from feet, inches, centimetres, metres or yards, so you can work directly from whatever measurements you already have on hand rather than converting them yourself first. The calculator converts each dimension to feet, multiplies them together, and returns the volume in cubic feet, along with the same figure recalculated in cubic inches, cubic yards, cubic metres, litres, US gallons and Imperial gallons. A detail panel below the results shows each dimension as entered and converted to feet, plus the final volume, so you can check the working. Use it when comparing a US-sourced spec sheet, appliance manual or storage listing against New Zealand's metric standard, when quoting a concrete pour or skip bin in the unit your supplier uses, or when working out how much space a room, box or tank actually holds. It only calculates the volume of a rectangular, box-shaped space; for an irregular shape, measure the smallest rectangular box that would enclose it and adjust the result accordingly. Results are rounded to three decimal places for cubic feet and one decimal place for litres and gallons.

Calculate.co.nz is proud to be partnered with Premium Homes, a recognised leader in eco-friendly, sustainable, and energy-efficient homebuilding. With a dedicated team and award-winning experience, they create homes that prioritise health, comfort, and long-term performance. Their founders, Andrew and Kelly, set out to raise the standard of residential construction in New Zealand by combining practical building expertise with a clear commitment to doing things better for homeowners.

Standard formula Volume = Length x Width x Height. Conversion factors: 1 ft = 12 in = 30.48 cm = 0.3048 m.

1. Dimensions

Input unit

Length (ft)

Width (ft)

Height / Depth (ft)

2. Quick Reference

Common conversion factors to cubic feet:

1 cubic yard= 27 cubic feet

1 cubic metre= 35.3147 cu ft

1 cubic foot= 1,728 cubic inches

1 cubic foot= 28.3168 litres

1 cubic foot= 7.4805 US gallons

1 cubic foot= 6.2288 Imperial gallons

Worked Example

A room 10 ft x 8 ft x 6 ft:

Volume = 10 x 8 x 6 = 480 cubic feet

= 829,440 cubic inches

= 17.778 cubic yards

= 13.592 cubic metres

= 13,592.1 litres

Volume Result

Cubic Feet
480
ft³

Cubic Inches

829,440

in³

Cubic Yards

17.778

yd³

Cubic Metres

13.592

m³

Volume Conversions

Cubic feet480 ft³

Cubic inches829,440 in³

Cubic yards17.778 yd³

Cubic metres13.592 m³

Litres13,592.1 L

US gallons3,590.6 US gal

Imperial gallons2,989.8 Imp gal

Calculation

Input unitfeet

Length (as entered)10 ft

Width (as entered)8 ft

Height / Depth (as entered)6 ft

Length in feet10.000 ft

Width in feet8.000 ft

Height in feet6.000 ft

Volume480.000 ft³

How to Calculate Cubic Feet

Cubic feet measure the three-dimensional volume of a rectangular space or object. The formula is straightforward:

Cubic feet = Length (ft) x Width (ft) x Height (ft)

If your measurements are in a different unit, convert each dimension to feet first, then multiply. For example, 12 inches = 1 foot, so a dimension of 36 inches becomes 3 feet. A dimension of 2 metres becomes approximately 6.562 feet (since 1 metre = 3.28084 feet).

Unit Conversions to Feet

From	To Feet	Multiply by
Inches	Feet	0.083333 (divide by 12)
Centimetres	Feet	0.032808 (divide by 30.48)
Metres	Feet	3.28084
Yards	Feet	3

Cubic Feet Conversions

To Convert	Multiply Cubic Feet by
Cubic inches	1,728
Cubic yards	0.037037 (divide by 27)
Cubic metres	0.028317
Litres	28.3168
US gallons	7.48052
Imperial gallons	6.22884

Common Uses for Cubic Feet

Cubic feet come up in a wide range of practical situations:

Heating and cooling: Air conditioning and heat pump sizing is often given in BTU per hour, which depends on the cubic footage of the room. HVAC equipment is frequently rated in tons of cooling capacity relative to cubic feet of conditioned space.
Shipping and freight: Couriers and freight companies calculate volumetric weight or dimensional weight based on cubic feet or cubic inches. Knowing the cubic footage of a package helps you estimate shipping costs.
Concrete and fill: Concrete is typically sold by the cubic metre in New Zealand, but if you are working from a US specification or an older plan, you may need to convert cubic feet to cubic metres. 1 cubic foot is approximately 0.0283 cubic metres.
Storage and moving: Self-storage units and moving trucks are advertised in cubic feet. Knowing the total cubic footage of your belongings helps you choose the right size unit or truck.
Aquariums and tanks: Tank volume is often expressed in litres or gallons, but calculating cubic feet first and then converting is a reliable approach.
Skip bins and waste disposal: Skip bin capacity in New Zealand is often quoted in cubic metres, but US-sourced guides may use cubic feet. This calculator converts directly between the two.

Cubic Feet vs Cubic Metres

New Zealand uses the metric system, so cubic metres (m³) are the standard unit for volume in construction, engineering, and trade. However, cubic feet are still commonly used in US-sourced content, appliance specifications, and some older building plans. One cubic metre equals approximately 35.315 cubic feet. One cubic foot equals approximately 0.0283 cubic metres.

For building and construction work in New Zealand, it is worth converting to cubic metres for consistency with supplier pricing and material specifications. This calculator converts both ways.

Related Calculators

Sources and method: Volume = Length x Width x Height. Conversion factors from NIST Special Publication 1038 (The International System of Units) and standard imperial-to-metric definitions: 1 inch = 25.4 mm exactly; 1 foot = 12 inches = 0.3048 m exactly; 1 yard = 3 feet; 1 US gallon = 231 cubic inches; 1 Imperial gallon = 4.54609 litres.

This calculator computes volume for rectangular (box-shaped) objects only. For irregular shapes, calculate the volume of the enclosing rectangular box and adjust for the shape. Results are rounded to 3 decimal places for cubic feet and to 1 decimal place for litres and gallons.