Cubic Feet to Gallon Converter
Convert cubic feet (ft³) to gallons for tanks, pools, shipping containers, and more.
Conversion Result
📐 Conversion Formulas
Cubic Feet to Gallons:
Key Constants:
- 1 ft³ = 28.316846592 liters (exact)
- 1 US gallon = 3.785411784 liters
- 1 Imperial gallon = 4.54609 liters
- Therefore: 1 ft³ = 7.48052 US gal = 6.22884 Imp gal
Where does 28.317 L/ft³ come from?
1 foot = 30.48 cm exactly. So 1 ft³ = (30.48)³ cm³ = 28,316.846592 cm³ = 28.316846592 liters.
📝 Step-by-Step Calculation
Enter a value and convert to see the step-by-step breakdown.
Understanding Cubic Feet and Gallons
Converting cubic feet to gallons is essential for calculating liquid capacity of tanks, pools, aquariums, and shipping containers. Understanding this conversion helps with water usage planning, fuel storage, and construction projects.
What Is a Cubic Foot?
A cubic foot (ft³) is the volume of a cube measuring 1 foot on each side. Since 1 foot = 12 inches = 30.48 cm, a cubic foot equals 1,728 cubic inches or about 28.317 liters. Cubic feet are commonly used in the US for measuring:
- Tank and pool volumes
- Shipping container capacity
- Refrigerator and freezer space
- HVAC airflow rates
- Construction materials (soil, concrete, gravel)
US vs Imperial Gallons
The two gallon types give different results:
- 1 cubic foot = 7.48052 US gallons (used in United States)
- 1 cubic foot = 6.22884 Imperial gallons (used in UK, Canada historically)
The Imperial gallon is larger (4.546 L vs 3.785 L), so fewer Imperial gallons fit in the same volume.
Practical Applications
Common uses for this conversion include:
- Swimming pools: Calculate water volume for chemical treatment
- Aquariums: Determine tank capacity in gallons
- Water tanks: Size storage tanks for homes and farms
- Shipping: Calculate liquid cargo capacity
Quick Reference Table
Common cubic feet to gallon conversions:
| Cubic Feet (ft³) | US Gallons | Imperial Gallons | Liters |
|---|---|---|---|
| 1 | 7.48 | 6.23 | 28.32 |
| 5 | 37.40 | 31.14 | 141.58 |
| 10 | 74.81 | 62.29 | 283.17 |
| 25 | 187.01 | 155.72 | 707.92 |
| 50 | 374.03 | 311.44 | 1,415.84 |
| 100 | 748.05 | 622.88 | 2,831.68 |
| 133.68 | 1,000 | 832.67 | 3,785.41 |
| 500 | 3,740.26 | 3,114.42 | 14,158.42 |
Frequently Asked Questions
1 cubic foot equals 7.48052 US gallons or 6.22884 Imperial gallons. The difference stems from the different gallon definitions.
Multiply cubic feet by 7.48052 for US gallons, or by 6.22884 for Imperial gallons. For example: 10 ft³ × 7.48052 = 74.81 US gallons.
A US gallon is 3.785 liters, while an Imperial gallon is 4.546 liters—about 20% larger. This means fewer Imperial gallons fit in the same volume.
A 1000 US gallon tank is about 133.68 cubic feet. A 1000 Imperial gallon tank is about 160.54 cubic feet.
First calculate the pool's volume in cubic feet (length × width × average depth, all in feet). Then multiply by 7.48 to get US gallons. For example: a 20 × 10 × 5 ft pool = 1000 ft³ = 7,481 gallons.
The foot and gallon were defined independently at different times. A cubic foot is based on the 12-inch foot, while the US gallon was defined as 231 cubic inches (an arbitrary historical choice). These definitions don't create a simple ratio.
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