Gallon Calculator - Convert Gallons to Cups, Liters, Cubic Feet and More
Free gallon calculator. Convert gallons to cups, liters, cubic feet and inches, quarts, pints, fluid ounces, and even raindrops! Supports US and UK gallons. Also convert water gallons to weight (pounds and kilograms). Perfect for volume conversions and water weight calculations.
Last updated: January 23, 2026
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💡 Volume Converter
Input any variable and all others will fill in automatically!
Conversion Facts:
- • 1 US gallon = 3.785 liters
- • 1 UK gallon = 4.546 liters
- • 1 gallon = 4 quarts = 8 pints = 16 cups
- • 1 US gallon = 128 fluid ounces
- • Water density changes with temperature
Gallon Calculator Features
Modes
Volume Converter & Water Weight Converter
Switch between volume conversion and water gallons to weight conversion
Units
Gallons, Liters, Cubic, Quarts, Pints, Cups, and more
Convert between gallons, liters, cubic feet/inches/yards, quarts, pints, fluid ounces, cups, tablespoons, teaspoons, and even raindrops
Gallon Types
US gal, UK gal, US dry gal, 1k US gal
Support for US gallons, UK gallons, US dry gallons, and 1000 US gallons
Features
Weight in kg or lb
Convert water gallons to weight with temperature-dependent density calculations
Directions
Input any variable, all others update
Enter any value in any unit and all other fields will update automatically
Speed
Instant calculations
See results immediately as you enter or change values
Quick Example Result
Converting 1 US gallon to other units:
Input
1 US gal
Result
3.785 L
How Our Gallon Calculator Works
Our gallon calculator is a comprehensive converter that helps you convert gallons to cups, liters, cubic feet and inches, quarts, pints, fluid ounces, and even raindrops! Just input one of the values, and the rest will fill in automatically! It can convert both US and UK gallons. Our calculator can also convert gallons of water to pounds and kilograms.
How to Use the Calculator
Step 1: Select Mode
Choose between "Volume converter" or "Water gallons to weight converter". The volume converter mode allows you to convert between gallons and various volume units. The water weight converter mode converts gallons of water to weight (pounds or kilograms).
Step 2: Enter Value
In volume converter mode, enter a value in any field (gallons, liters, cubic units, quarts, pints, fluid ounces, cups, or raindrops). In water weight mode, enter either gallons or weight.
Step 3: Select Units
Select the appropriate unit from the dropdown menu for each field. The calculator supports US gallons, UK gallons, US dry gallons, liters, cubic feet/inches/yards, quarts, pints, fluid ounces, cups, tablespoons, teaspoons, and more.
Step 4: View Results
All other fields will automatically update to show equivalent values. In water weight mode, you can also select the water temperature to get more accurate weight calculations.
What is a Gallon?
A gallon is a unit of volume. It's bigger than a pint, liter, and fluid ounce, but smaller than cubic foot and a US barrel. Our calculator has four unit options correlated to gallons:
UK Gallons
Used in the United Kingdom and some Commonwealth countries. 1 UK gallon = 4.546 liters= 1.201 US gallons. The UK gallon is approximately 20% larger than the US gallon.
US Gallons
Used in the United States. 1 US gallon = 3.785 liters = 0.8317 UK gallons. This is the standard gallon used in the US for liquid measurements.
US Dry Gallons
Used for measuring dry goods in the United States. 1 US dry gallon = 4.405 liters. Less commonly used than liquid gallons.
1000 US Gallons
A large unit for industrial or commercial applications. 1k US gallons = 3,785.412 liters. Useful for large-scale volume measurements.
1 gallon is equal to 4 quarts, 8 pints, or 16 cups – so exactly the daily water intake for an average male adult.
Convert Liters to Gallons – Metric Units
Here's how gallons convert to metric units:
| 1 US gallon | 1 UK gallon | |
|---|---|---|
| milliliter (ml) | 3,785 | 4,546 |
| centiliter (cl) | 378.5 | 453.6 |
| liter (l) | 3.785 | 4.546 |
| hectoliter (hl) | 0.03785 | 0.04546 |
Convert Cubic Feet to Gallons & Convert Cubic Inches to Gallons
Here's how gallons convert to cubic units:
| 1 US gallon | 1 UK gallon | |
|---|---|---|
| cubic inches (cu in) | 231 | 277.4 |
| cubic feet (cu ft) | 0.13368 | 0.16054 |
| cubic yards (cu yd) | 0.004951 | 0.005946 |
Convert Quarts to Gallons
Here's how gallons relate to quarts and pints:
| 1 US gallon | 1 UK gallon | |
|---|---|---|
| US quarts | 4 | 4.804 |
| UK quarts | 3.331 | 4 |
| US pints | 8 | 9.608 |
| UK pints | 6.661 | 8 |
Convert Ounces to Gallons
Here's how gallons relate to fluid ounces:
| 1 US gallon | 1 UK gallon | |
|---|---|---|
| US fluid ounces | 128 | 153.72 |
| UK fluid ounces | 133.23 | 160 |
Convert Gallons to Cups
Here's how gallons relate to cups and spoons:
| 1 US gallon | 1 UK gallon | |
|---|---|---|
| US customary cups | 16 | 19.215 |
| tablespoons (15ml) | 252.36 | 303.1 |
| teaspoons (5ml) | 757.1 | 909.2 |
Water – Gallons to Kilograms and Pounds
A well-known property of water is that 1 liter weighs approximately 1 kilogram. This is due to its density – the ratio of mass to volume. The density of water changes with temperature. Our gallon calculator has a default value for the density of water at 20°C (68°F).
Below, you can see how much 1 US and UK gallons weigh at three different temperatures:
| 1 US gallon | 1 UK gallon | |
|---|---|---|
| 4°C / 39.2°F | 3.7856 kg / 8.346 lb | 4.546 kg / 10.023 lb |
| 21°C / 69.8°F | 3.778 kg / 8.33 lb | 4.538 kg / 10.004 lb |
| 30°C / 86°F | 3.769 kg / 8.31 lb | 4.527 kg / 9.98 lb |
As you see, the higher the temperature, the lighter water is. This is because water expands as it heats up, so the same volume weighs less at higher temperatures.
Practical Applications
This calculator is essential for various practical scenarios:
Pool & Aquarium Volume
Calculate how many gallons your pool or aquarium can hold. Convert from cubic feet or cubic inches to gallons to determine water capacity and treatment requirements.
Cooking & Baking
Convert recipe measurements between gallons, quarts, pints, cups, and fluid ounces. Perfect when scaling recipes up or down.
Water Weight Calculations
Determine the weight of water in gallons for shipping, storage, or structural calculations. Essential for understanding load requirements.
Industrial Applications
Convert between gallons and cubic meters or cubic feet for industrial processes, tank sizing, and fluid management systems.
Need other conversion tools? Check out our volume conversion and kg to gallons converter.
Get Custom Calculator for Your PlatformGallon Conversion Examples
Input:
- Gallons: 5 US gal
Calculation:
- Formula: Liters = Gallons × 3.785412
- Liters = 5 × 3.785412
- Liters = 18.927
Result: 5 US gallons = 18.927 liters
This is a common conversion for liquid measurements.
Input:
- Cubic Feet: 10 cu ft
Calculation:
- Formula: Gallons = Cubic Feet × 7.48
- Gallons = 10 × 7.48
- Gallons = 74.8
Result: 10 cubic feet = 74.8 US gallons
This is useful for calculating pool or tank volumes.
Input:
- Gallons: 2 US gal
- Temperature: 21°C / 69.8°F
Calculation:
- Convert to liters: 2 × 3.785412 = 7.571 L
- Density at 21°C: 0.998 kg/L
- Weight: 7.571 × 0.998 = 7.556 kg
- Weight in pounds: 7.556 × 2.20462 = 16.66 lb
Result: 2 US gallons of water = 7.556 kg / 16.66 lb
This demonstrates water weight conversion at room temperature.
1 US gal
=
4 quarts
1 US gal
=
16 cups
1 US gal
=
128 fl oz
Frequently Asked Questions
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