How many ml are in a gallon?

Volume unit converter

US Customary System vs. Imperial System

When I first learned about liquid measurements, I discovered that the answer to “how many ml in a gallon?” depends on the system you use. In the US, we rely on the Customary System, while in the UK and other regions the Imperial System is common.

1. US Customary System: Uses units like ounces, cups, pints, quarts, and gallons.
2. Imperial System: Also uses gallons, pints, and ounces—but the values differ from the US system.

Milliliters: A Metric Unit

Milliliters (ml) are a standard metric unit used worldwide. Since the metric system is decimal-based, converting between units is simple.

Milliliters are ideal for measuring small volumes—whether for recipes, medications, or laboratory experiments.

How Many ml in a US Gallon?

In the US Customary System, 1 gallon equals 3,785.41 ml. Simply multiply the number of gallons by 3,785.41 to convert.

How Many ml in an Imperial Gallon?

For the Imperial System, 1 gallon is 4,546.09 ml. Use this factor when working with Imperial measurements.

Other Liquid Measurement Conversions

Here are some useful conversion factors:

• 1 US fluid ounce = 29.5735 ml
• 1 US cup = 236.588 ml
• 1 US pint = 473.176 ml
• 1 US quart = 946.353 ml
• 1 Imperial fluid ounce = 28.4131 ml
• 1 Imperial cup = 284.131 ml
• 1 Imperial pint = 568.261 ml
• 1 Imperial quart = 1,136.52 ml

Converting Gallons to Milliliters

The conversion is simple:

• For US Gallons: Multiply by 3,785.41 (e.g., 5 US gallons × 3,785.41 = 18,927.05 ml).
• For Imperial Gallons: Multiply by 4,546.09 (e.g., 5 Imperial gallons × 4,546.09 = 22,730.45 ml).

Conversion Tables

US Gallons to Milliliters

Imperial Gallons to Milliliters

Comparing US and Imperial Gallons

In short:

• 1 US gallon = 3,785.41 ml
• 1 Imperial gallon = 4,546.09 ml

Knowing which gallon you’re using is essential for accurate conversions.

Practical Applications

These conversions come in handy for:

• Cooking & Baking: Measuring ingredients accurately.
• Automotive Maintenance: Converting oil or coolant capacities.
• Gardening: Mixing fertilizers and pesticides.

Other Common Liquid Conversions

It’s useful to know additional conversions, such as:

• 1 US gallon = 128 US fluid ounces
• 1 US quart = 32 US fluid ounces
• 1 US pint = 16 US fluid ounces
• 1 US cup = 8 US fluid ounces
• 1 US fluid ounce = 29.57 ml

Tips for Remembering Conversions

To keep these numbers straight, I like to:

• Create a quick reference sheet.
• Use mnemonic devices for key conversion factors.
• Practice conversions regularly.

Converting Milliliters to Gallons

It’s also important to convert ml back to gallons. Here are the inverse factors:

• 1 ml = 0.000264172 US gallons
• 1 ml = 0.000219969 Imperial gallons

Conversion Tables: Milliliters to Gallons

Milliliters to US Gallons

Milliliters to Imperial Gallons

Online Conversion Tools

If you prefer not to do the math yourself, many online tools can quickly convert between gallons, milliliters, liters, quarts, and more.

To recap, remember that 1 US gallon = 3,785.41 ml and 1 Imperial gallon = 4,546.09 ml.

Myriam Minne

Hi, I'm Myriam—a social media expert and passionate cook. I earned my chef’s diploma at the Spermatic Hotel School in Bruges and spent two years perfecting my pastry skills. I love exploring recipes from around the world and spending hours in the kitchen experimenting with new techniques. Every time I put on my apron, I create desserts that are both delicious and meaningful.