How many liters are in a US gallon?

About 3.7854. The US gallon is defined as exactly 231 cubic inches, which equals 3.785411784 liters.

How many milliliters are in a US cup?

About 236.6 mL. A US cup is 1/16 of a gallon (8 fluid ounces), which works out to roughly 236.6 milliliters.

Are these US or imperial units?

US customary liquid units. A UK (imperial) pint or gallon is about 20% larger than the US version, so this converter's gallon, quart, pint, cup and fluid ounce are all the US sizes.

How do you convert liters to cups?

Multiply liters by about 4.2268, since 1 liter is 1000 mL and a US cup is about 236.6 mL. So 2 L is roughly 8.45 cups.

How many tablespoons are in a cup?

16 US tablespoons make one US cup (a tablespoon is 1/2 fluid ounce and a cup is 8 fluid ounces), and 3 teaspoons make one tablespoon.

Is a cubic centimeter the same as a milliliter?

Yes. One cubic centimeter (cm³, sometimes "cc") equals exactly one milliliter, so the two are interchangeable.

To convert a volume, choose the unit you have and the unit you want. The US gallon is defined as exactly 231 cubic inches, which is 3.785411784 liters — so 1 gallon is about 3.7854 L, 1 liter is about 4.23 US cups, and 1 cup is about 237 milliliters. All the smaller US units divide down from the gallon.

Volume Converter — liters, gallons, cups, milliliters & more

Volume

From

Converting 1 from gallon to liter.

Converted volume3.7854in Liters (L)

1 US gallons (gal) converts to

Liters (L): 3.7854
Milliliters (mL): 3,785.4118
Cubic meters (m³): 0.0038
Cubic centimeters (cm³): 3,785.4118
Cubic inches (in³): 231
Cubic feet (ft³): 0.1337
US gallons (gal): 1
US quarts (qt): 4
US pints (pt): 8
US cups: 16
US fluid ounces (fl oz): 128
Tablespoons (tbsp): 256
Teaspoons (tsp): 768

Quick examples

Converted volume3.7854

How it works

Volume conversion links the metric litre to the US customary liquid units through one exact definition (NIST SP 811):

1 US gallon = 231 cubic inches = 3.785411784 L (exact).
The US liquid units halve down from there: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces; 1 tablespoon = 1/2 fluid ounce, 1 teaspoon = 1/3 tablespoon.
Metric volume steps by powers of ten: 1 L = 1000 mL, and 1 mL = 1 cm³.

The calculator converts your value to the base unit (the litre) and then to the unit you want, so any pairing — gallon↔litre, litre↔cup, cup↔millilitre — works the same way. Note: these are US liquid units; UK/imperial pints and gallons are about 20% larger, so use US values here.

Worked example

Converting 1 US gallon to liters:

1 gal × 3.785411784 = 3.7854 L

Going the other way, 1 liter ≈ 4.2268 US cups, and 1 US cup ≈ 236.6 mL.

Frequently asked questions

How many liters are in a US gallon?: About 3.7854. The US gallon is defined as exactly 231 cubic inches, which equals 3.785411784 liters.
How many milliliters are in a US cup?: About 236.6 mL. A US cup is 1/16 of a gallon (8 fluid ounces), which works out to roughly 236.6 milliliters.
Are these US or imperial units?: US customary liquid units. A UK (imperial) pint or gallon is about 20% larger than the US version, so this converter's gallon, quart, pint, cup and fluid ounce are all the US sizes.
How do you convert liters to cups?: Multiply liters by about 4.2268, since 1 liter is 1000 mL and a US cup is about 236.6 mL. So 2 L is roughly 8.45 cups.
How many tablespoons are in a cup?: 16 US tablespoons make one US cup (a tablespoon is 1/2 fluid ounce and a cup is 8 fluid ounces), and 3 teaspoons make one tablespoon.
Is a cubic centimeter the same as a milliliter?: Yes. One cubic centimeter (cm³, sometimes "cc") equals exactly one milliliter, so the two are interchangeable.

How we know this is right

Last reviewed: Aug 9, 2026
Precision: Rounded to 4 decimal places.

Read our methodology

Sources

National Institute of Standards and Technology (NIST) NIST Special Publication 811, "Guide for the Use of the International System of Units (SI)", Appendix B — the US liquid gallon is exactly 231 cubic inches = 3.785411784 L; 1 quart = 1/4 gallon, 1 pint = 1/8, 1 cup = 1/16, 1 fluid ounce = 1/128. · Reviewed Aug 9, 2026