Quick Summary
A cubic foot is a unit of volume that measures 1 foot x 1 foot x 1 foot, which equals 1728 cubic inches. One US gallon is 231 cubic inches. By dividing 1728 cubic inches per cubic foot by 231 cubic inches per gallon, we find that 7.481 gallons of water will fit in 1 cubic foot. In summary:
- 1 cubic foot = 1728 cubic inches
- 1 US gallon = 231 cubic inches
- 1728 cubic inches / 231 cubic inches per gallon = 7.481 gallons
So the quick answer is that 7.481 gallons of water will fit in 1 cubic foot.
What is a Cubic Foot?
A cubic foot is a unit of volume commonly used in the United States and United Kingdom. It measures one foot by one foot by one foot, forming a cube with 6 equal sides each measuring 1 foot in length.
Since there are 12 inches in 1 foot, a cubic foot contains 12 x 12 x 12 = 1728 cubic inches. 1728 cubic inches is the volume contained in a cube measuring 1 foot on each side.
Some key facts about the cubic foot:
- Abbreviated as cu ft or ft3
- 1 cubic foot = 1728 cubic inches exactly
- Used to measure volumes of liquids and solids
- Commonly used in construction, engineering, andarchitecture
Understanding what a cubic foot represents helps us calculate how much liquid, like water, can fit into this volume.
What is a US Gallon?
A US gallon is a unit of volume used to measure liquids such as water, milk, or gasoline. It is the most common gallon definition used in the United States.
One US gallon equals 231 cubic inches. This means a cube measuring 231 inches on each side would contain exactly 1 gallon.
Some key facts about the US gallon:
- Abbreviated as gal
- 1 US gallon = 231 cubic inches exactly
- Used to measure volumes of liquids like water, milk, or oil
- Equal to 3.785 liters
- Equal to 0.133680555 cubic feet
The US gallon helps us relate liquid volumes in gallons to cubic inch and cubic foot measurements.
Calculating Gallons in a Cubic Foot
Now we can calculate how many gallons will fit into 1 cubic foot:
- We know 1 cubic foot = 1728 cubic inches
- We know 1 US gallon = 231 cubic inches
- To find how many gallons are in 1 cubic foot, we divide cubic inches of 1 foot by cubic inches per gallon:
- 1728 cubic inches / 231 cubic inches per gallon = 7.481 gallons
So by dividing the total cubic inches in 1 cubic foot by the cubic inches in 1 gallon, we find that 7.481 US gallons will fit in 1 cubic foot.
Let’s visualize this using a table:
| Volume Unit | Cubic Inches |
|---|---|
| 1 cubic foot | 1728 in3 |
| 1 US gallon | 231 in3 |
This table helps show that when we divide the 1728 in3 in a cubic foot by the 231 in3 in a gallon, we get 7.481 gallons per cubic foot.
Converting Cubic Feet to Gallons Example
Let’s look at an example converting cubic feet to gallons:
* If you had a water tank measuring 2 feet by 2 feet by 2 feet, what is its volume in gallons?
- The tank measures 2 cubic feet (2 x 2 x 2)
- We calculated 1 cubic foot holds 7.481 gallons
- So 2 cubic feet will hold 2 x 7.481 = 14.962 gallons
For a 2 x 2 x 2 cubic foot tank, the volume in gallons is 14.962.
Applications and Uses
Knowing the gallon-to-cubic-foot conversion is useful for:
- Measuring rainwater, stormwater, or drinking water in drainage systems, water tanks, or reservoirs
- Calculating fluid capacities for pools, water heaters, or gas tanks
- Determining irrigation water requirements for lawns or crops
- Sizing piping for water supply systems
- Engineering and scientific applications involving liquid volumes
Professionals like farmers, plumbers, engineers, and scientists may need to calculate gallons to cubic feet conversions regularly in their work.
International Gallon Variations
It’s important to note there are several different gallon definitions used around the world:
- US gallon – 231 cubic inches
- Imperial gallon (UK) – 277.420 cubic inches
- Canadian gallon – 231 cubic inches
- Australian gallon – 137.428 cubic inches
The US and Canadian gallons are identical. The Imperial (UK) gallon is about 20% larger than the US gallon. The Australian gallon is significantly smaller than the other standards.
This means the number of gallons per cubic foot conversions will differ slightly depending on the gallon definition used:
| Gallon Type | Gallons per Cubic Foot |
|---|---|
| US Gallon | 7.481 |
| Imperial Gallon (UK) | 6.229 |
| Canadian Gallon | 7.481 |
| Australian Gallon | 12.698 |
So the conversion can vary between 6.229 Imperial gallons per cubic foot up to 12.698 Australian gallons, depending on the gallon definition. It’s always important to specify which gallon unit you are using.
Converting Other Units to Cubic Feet
We can use similar conversions to find cubic feet values for other volume units:
Cubic inches to cubic feet
- 1 cubic foot = 1728 cubic inches
- To convert cubic inches to cubic feet, divide by 1728
- Examples:
- 384 cu in / 1728 = 0.222 cu ft
- 8000 cu in / 1728 = 4.632 cu ft
Cubic centimeters (cm) to cubic feet
- 1 cubic foot = 28316.846 cubic cm
- To convert cm3 to cu ft, divide by 28316.846
- Examples:
- 100000 cm3 / 28316.846 = 3.534 cu ft
- 55000 cm3 / 28316.846 = 1.941 cu ft
Liters (L) to cubic feet
- 1 cubic foot = 28.316 L
- To convert L to cu ft, divide by 28.316
- Examples:
- 100 L / 28.316 = 3.534 cu ft
- 20 L / 28.316 = 0.707 cu ft
Milliliters (mL) to cubic feet
- 1 cubic foot = 28316.846 mL
- To convert mL to cu ft, divide by 28316.846
- Examples:
- 100000 mL / 28316.846 = 3.534 cu ft
- 50000 mL / 28316.846 = 1.767 cu ft
So cubic inches, centimeters, liters or milliliters can all be converted into cubic feet if needed.
Converting Cubic Feet to Other Units
We can also convert cubic feet to other units:
Cubic feet to cubic inches
- 1 cubic foot = 1728 cubic inches
- To convert cubic feet to inches, multiply by 1728
- Examples:
- 2 cu ft x 1728 = 3456 cu in
- 0.5 cu ft x 1728 = 864 cu in
Cubic feet to cubic centimeters (cm)
- 1 cubic foot = 28316.846 cm3
- To convert cu ft to cm3, multiply by 28316.846
- Examples:
- 4 cu ft x 28316.846 = 113267 cm3
- 0.25 cu ft x 28316.846 = 7079 cm3
Cubic feet to liters (L)
- 1 cubic foot = 28.316 L
- To convert cu ft to L, multiply by 28.316
- Examples:
- 3 cu ft x 28.316 = 84.95 L
- 0.75 cu ft x 28.316 = 21.24 L
Cubic feet to milliliters (mL)
- 1 cubic foot = 28316.846 mL
- To convert cu ft to mL, multiply by 28316.846
- Examples:
- 1 cu ft x 28316.846 = 28316 mL
- 0.5 cu ft x 28316.846 = 14158 mL
Being able to convert both to and from cubic feet for other units can be very handy for many volume and capacity calculations.
Cubic Foot Formulas
Some important formulas related to the cubic foot:
- Volume of a cube = Side length x Side length x Side length
- Volume of a cubic foot = 1 ft x 1 ft x 1 ft = 1 cubic foot
- Cubic feet = Length (ft) x Width (ft) x Height (ft)
- 1 cubic foot = 1728 cubic inches
- Cubic inches = Length (in) x Width (in) x Height (in)
Using these formulas you can calculate the cubic foot volume of any right rectangular prism shape, or convert between cubic inches and cubic feet.
Cubic Foot Conversions Table
This table summarizes some key cubic foot conversion factors:
| From | To | Conversion Factor |
|---|---|---|
| Cubic feet (cu ft) | Cubic inches (in3) | 1 cu ft = 1728 in3 |
| Cubic inches (in3) | Cubic feet (cu ft) | 1 in3 = 0.00058 cu ft |
| Cubic feet (cu ft) | US Gallons (gal) | 1 cu ft = 7.481 gal |
| US Gallons (gal) | Cubic feet (cu ft) | 1 gal = 0.1337 cu ft |
| Cubic feet (cu ft) | Liters (L) | 1 cu ft = 28.316 L |
| Liters (L) | Cubic feet (cu ft) | 1 L = 0.0353 cu ft |
This provides a quick reference for converting cubic feet to other common volume units.
Finding Capacity by Dimensions
We can combine the cubic foot conversion with its formulas to determine the capacity of a rectangular container based on its dimensions:
Steps:
- Measure the interior length, width and height in feet
- Calculate cubic feet using: cu ft = (length x width x height)
- Convert cubic feet to gallons using: gallons = cu ft x 7.481
Example
- Tank dimensions: 3 ft x 2 ft x 2 ft
- Cubic feet = (3 x 2 x 2) = 12 cu ft
- Gallons = 12 cu ft x 7.481 gal/cu ft = 89.77 gallons
So a rectangular tank 3 x 2 x 2 feet contains about 90 gallons.
This shows how the cubic foot’s conversion to gallons can help determine capacities based on interior dimensions.
Cubic Foot FAQs
What is the cubic foot used for?
The cubic foot is primarily used to measure volumes of liquids and solid materials in the United States and United Kingdom. Some examples include:
– Quantities of concrete, gravel, or soil used in construction
– Water volumes for pools, tanks, or rainfall
– Gas or liquid tank capacities
– Furniture and cargo dimensions and capacity
– Warehouse inventory space
Is a cubic foot bigger than a gallon?
A cubic foot is substantially bigger than a gallon. One cubic foot holds 7.481 US gallons. So a cubic foot’s volume is 7 times larger than a single gallon.
How do you calculate cubic feet?
To calculate cubic feet of a rectangular prism, multiply the length x width x height, with dimensions entered in feet. For other shapes, divide the total cubic inch volume by 1728 inches per cubic foot.
How many cubic feet are in a yard?
There are 27 cubic feet in a cubic yard since a yard is 3 feet x 3 feet x 3 feet (27 cubic feet).
How many cubic feet are in an acre-foot?
An acre-foot is the volume of water covering 1 acre to a depth of 1 foot. Since an acre is 43,560 square feet, an acre-foot equals 43,560 cubic feet.
Conclusion
In summary, a cubic foot is a unit equal to 1 foot x 1 foot x 1 foot or 1728 cubic inches. We find that 1 cubic foot can hold 7.481 US gallons. This conversion allows us to determine capacities of tanks and containers when we know their cubic foot volume. Understanding cubic feet and gallons conversions is important for many science, engineering, construction and industrial applications.
