Gallon Calculator - Convert Between Gallons and Other Volume Units

Free gallon calculator to instantly convert between US gallons, liters, cups, pints, quarts, fluid ounces, milliliters, and other volume units with accurate results

Updated: November 2025 • Free Tool

Gallon Calculator

Result

Converted Volume
3.78541 liters
Conversion Formula
1 gallon × 3.78541 = 3.78541 liters
Conversion Factor
1 gallon = 3.78541 liters

Quick Reference Conversions

What is a Gallon Calculator?

A Gallon Calculator is a free tool that instantly converts volume measurements between gallons and other units. It handles US gallons, imperial gallons, liters, cups, fluid ounces, and cooking measurements to help you convert any volume quickly and accurately.

This calculator is essential for:

  • Automotive - Convert fuel tank capacities and fuel consumption calculations
  • Cooking & Baking - Convert recipe measurements between imperial and metric systems
  • Home Improvement - Calculate paint, water, and other liquid quantities for projects
  • Aquariums & Pools - Determine tank volumes and water treatment chemical amounts
  • International Travel - Convert fuel prices and quantities between countries

For other volume conversions, try our Volume Converter for comprehensive liquid measurements, or our Weight Converter for mass calculations.

How the Gallon Calculator Works

The calculator uses standard conversion factors to transform values between different volume units:

Conversion Process:
1. Convert input value to liters (base unit)
2. Convert liters to target unit

Key Conversion Factors:

  • 1 US gallon = 3.78541 liters
  • 1 imperial gallon = 4.54609 liters
  • 1 gallon = 16 cups
  • 1 gallon = 128 fluid ounces
  • 1 gallon = 4 quarts
  • 1 gallon = 8 pints

Key Gallon Measurement Concepts

US Gallon

The standard gallon used in the United States. Equal to 3.78541 liters or 128 fluid ounces. Commonly used for fuel and milk measurements.

Imperial Gallon

Used in the UK and some Commonwealth countries. Equal to 4.54609 liters. About 20% larger than a US gallon.

Metric System

Based on liters and milliliters. Easy conversions: 1 liter = 1000 milliliters. Used globally and in scientific work.

US Imperial Units

Includes cups, pints, quarts, and fluid ounces. 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces.

How to Use This Calculator

1

Enter Volume Amount

Type the volume measurement you want to convert (e.g., 2, 5.5, 100)

2

Select From Unit

Choose your starting unit (gallons, liters, cups, etc.)

3

Select To Unit

Choose the unit you want to convert to

4

View Results

See instant conversion with formula and quick reference

Pro Tip: Use the swap button (⇄) to quickly reverse your conversion units!

Benefits of Using This Calculator

  • Instant Conversions: Get accurate gallon conversions immediately without manual calculations.
  • Multiple Units: Convert between US gallons, imperial gallons, liters, cups, and more.
  • Cooking Friendly: Perfect for recipe conversions and kitchen measurements.
  • Scientific Accuracy: Uses precise conversion factors for engineering and scientific work.
  • Quick Reference: View your volume in all available units simultaneously for easy comparison.

Common Gallon Conversions

1. Fuel Measurements

Converting fuel gallons to liters for international travel. Example: 10 gallons ≈ 37.85 liters of gasoline.

2. Water Tank Capacity

Converting tank volumes for pools or aquariums. Example: 50 gallons ≈ 189.27 liters of water.

3. Cooking Quantities

Converting large recipe quantities between units. Example: 2 gallons of milk ≈ 7.57 liters.

4. Paint & Liquid Products

Calculating paint amounts for projects. Example: 1 gallon of paint ≈ 3.78 liters for coverage calculations.

Gallon Calculator - Free online tool to convert between gallons, liters, cups, and fluid ounces with instant accurate results
Professional gallon calculator interface for converting between US gallons, imperial gallons, liters, cups, pints, quarts, fluid ounces, and cooking measurements. Features include real-time calculations, conversion formulas, quick reference tables, and mobile-friendly design.

Frequently Asked Questions (FAQ)

Q: How many liters are in a gallon?

A: One US gallon equals 3.78541 liters. This is the standard conversion used in the United States. UK (imperial) gallons are different, equal to 4.54609 liters.

Q: How do I convert gallons to cups?

A: To convert gallons to cups, multiply the number of gallons by 16. For example, 1 gallon equals 16 cups. This conversion is commonly used in cooking and recipes.

Q: What's the difference between US gallons and imperial gallons?

A: US gallons and imperial (UK) gallons are different measurements. One US gallon is 3.78541 liters, while one imperial gallon is 4.54609 liters. This calculator uses US gallons by default.

Q: How many gallons are in a liter?

A: One liter equals approximately 0.264172 US gallons. To convert liters to gallons, divide the number of liters by 3.78541.

Q: Can I use this calculator for fuel calculations?

A: Yes, this gallon calculator is perfect for fuel calculations. You can convert fuel quantities between gallons, liters, and other volume units for automotive and household purposes.

Q: How accurate is this gallon converter?

A: This calculator uses precise, standardized conversion factors and provides results accurate to multiple decimal places. It's suitable for cooking, scientific work, and everyday conversions.