How to use the cubic feet calculator
On the first tab, add each space you want to measure: a room, a closet, a cabinet, a storage bin, a trailer. Type its length, width and height. You can type feet, inches or both, such as 12'6" or 150 in, and the page converts. The total appears at once in cubic feet, cubic inches, cubic yards, cubic meters, liters and US gallons, along with the weight of the water that would fill it. If the thing you are measuring has a published volume, such as a moving truck or a shipping container, pick it from the list instead. The picture draws the space to scale and fills it with unit cubes so you can see what a cubic foot looks like. Nothing you type leaves your device unless you make a share link.
The formula
A cubic foot is a cube 1 foot long, 1 foot wide and 1 foot high. A space that is 12 feet long, 10 feet wide and 8 feet high holds 12 × 10 × 8 = 960 cubic feet. Divide by 27 to get cubic yards: 960 ÷ 27 = 35.56. In metric, that room is 27.18 cubic meters. Measure everything in the same unit before you multiply. If you measure in inches, you get cubic inches, and a cubic foot is 1,728 of them, not 12.
Cubic feet to gallons
A US gallon is 231 cubic inches, and a cubic foot is 12 × 12 × 12 = 1,728 cubic inches. So one cubic foot holds 1,728 ÷ 231 = 7.4805 US gallons, or 28.317 liters. Going the other way, one gallon is about 0.13368 cubic foot. For example, 10 cubic feet is 10 × 1,728 ÷ 231 = 74.8 gallons. The Cubic feet to gallons tab does this for any amount and also gives quarts, pints, cups, fluid ounces, liters, milliliters, cubic inches, cubic yards and cubic meters, and it shows the arithmetic. This is the US gallon. The imperial gallon used in the UK is larger, and this page does not use it.
Will it fit?
The Will it fit tab compares a load with a space by volume. Type the load as a box or a volume, pick a truck or container or type the space, and it shows the share of the space the load fills, how many loads would fit, and how many trips it takes if it does not. A fit by volume is the best case. Furniture does not stack like cubes, so the box you type for the load should include the gaps, and the usable share box lets you hold some of the space back. The page does not choose that number for you.
Truck and container volumes need care. U-Haul's page lists a 10-foot truck as 402 cubic feet with an inside size of 9 feet 11 inches by 6 feet 4 inches by 6 feet 2 inches, but those three sizes multiply to about 387 cubic feet. The page does not say why they differ, and the same is true of its other trucks, so the preset list uses each maker's own listed volume. Both makers say the equipment you get may differ.
Refrigerators and freezers
The cubic feet on an appliance label is a measure of total interior volume, worked out by an industry test method (AHAM HRF-1, which the Department of Energy's rules point to). It is roughly the volume the inside would hold if you emptied it and filled it with water, so it counts nooks that food never goes in. Shelves, drawers and ice buckets then take space from what you can use. One appliance review site reported that some labels overstate usable space by as much as 30 percent, so compare usable space with a tape measure before you buy. This is why the page measures boxes you can measure and does not try to predict a label.
Where the numbers come from
A foot is exactly 0.3048 meter, so a cubic foot is exactly 0.028316846592 cubic meter, and a cubic meter is about 35.315 cubic feet. A US gallon is 231 cubic inches, which is exactly 3.785411784 liters. NIST's conversion tables print the gallon as 3.785412 × 10⁻³ cubic meter, which matches. The pounds of water use a density of 998.2 kilograms per cubic meter, water at 20 °C (68 °F), which is about 62.3 pounds per cubic foot. Water is a little heavier when colder, so the live Water weight calculator lets you pick the temperature. The page rounds only what it shows. There is no building code for a volume, so none is named.
What people use it for
- Moving: the size of the truck against the size of what you own.
- Storage: a unit, a shed, a trailer or a closet by its cubic feet.
- Tanks, tubs, aquariums and barrels, from a box shape to gallons.
- Airflow and heating or cooling work, where a room's volume matters.
- Checking a shipping container or a freezer against what you want to put in it.
Common mistakes
- Mixing units. 12 feet × 10 feet × 96 inches is not 11,520 of anything useful. Convert first, or type the unit and let the page do it.
- Dividing by 12 instead of 1,728. Cubic inches to cubic feet is ÷ 1,728, and square inches to square feet is ÷ 144.
- Using the outside size. Walls, shelves and insulation take space. Measure the inside.
- Treating a fit by volume as a fit. Gaps and odd shapes use space.
- Mixing up gallons. A US gallon is 3.785 liters, and the UK imperial gallon is bigger.
Questions
How many gallons are in a cubic foot?
7.4805 US gallons. A cubic foot is 1,728 cubic inches and a gallon is 231, so 1,728 ÷ 231 = 7.4805.
How many cubic feet are in a gallon?
About 0.13368. A gallon is 231 cubic inches, and 231 ÷ 1,728 = 0.13368.
How many cubic feet are in a cubic yard?
27, because a cubic yard is 3 × 3 × 3 feet.
How many pounds does a cubic foot of water weigh?
About 62.3 pounds at 68 °F. It is a little more when the water is colder and a little less when it is warmer.
How is this different from the volume calculator?
The Volume calculator starts from a shape, such as a cylinder or a sphere, and a depth, and shows what that volume would weigh as concrete, sand or soil. This page starts from boxes and spaces and answers cubic feet, gallons and whether one volume fits in another.
Can I use metric?
Yes. Press Metric to type meters and centimeters. The answer leads with cubic meters and liters and still shows cubic feet and gallons. The page opens in the system your browser's region uses and remembers your choice on this device.
Can I share my result?
Yes. Share makes a link with a picture for Facebook, X and Pinterest, a link you can copy, a Share button on phones, and a short video for TikTok made on your device. The link keeps only the sizes and the unit choice, for 90 days.