Fluid Ounces to Milliliters Converter

Last updated: September 16, 2026

What a fluid ounce and a milliliter measure

A fluid ounce is a unit of liquid volume, not weight, even though it shares the word "ounce" with the weight unit. It is part of the U.S. customary and imperial systems and is used for drinks, recipes, and medicine. A milliliter is the metric unit for the same job: it is one thousandth of a liter, and it is used almost everywhere outside the United States.

Because a fluid ounce and a milliliter both measure volume, converting between them is a simple, exact multiplication once you know which fluid ounce you mean.

Converting US fluid ounces to milliliters

To change U.S. fluid ounces into milliliters, multiply by 29.5735.

For example, a 12 fl oz soda can holds 12 × 29.5735 = about 355 mL, which is exactly why cans outside the U.S. are often labeled 355 mL. A standard 16 fl oz water bottle holds about 473 mL.

Fluid ounces to milliliters conversion table

US fluid ounce vs UK (imperial) fluid ounce

This is the detail that trips people up. The U.S. and the UK use fluid ounces of slightly different sizes:

The systems also count differently: a U.S. pint is 16 fluid ounces, while a UK pint is 20. So a recipe or bottle from Britain will not match a U.S. one ounce for ounce. This converter uses the U.S. fluid ounce.

Everyday uses: cooking, drinks, and medicine

Kitchen recipes often mix U.S. cups and fluid ounces with metric milliliters, so converting keeps your measurements consistent. Drink sizes are another common case, from a 12 fl oz can to a 20 fl oz bottle. In medicine, doses are frequently written in milliliters, and a fluid ounce is often rounded to a convenient 30 mL for dosing cups — close to the exact 29.57 mL, but always follow the label or a pharmacist for medicine.

How fluid ounces fit with cups, pints, and liters

Seeing the whole family of volume units makes conversions faster:

• 8 US fluid ounces = 1 US cup = about 236.6 mL
• 16 US fluid ounces = 1 US pint = about 473 mL
• 33.814 US fluid ounces = 1 liter

That last line is handy: a 1-liter bottle holds just under 34 U.S. fluid ounces.

Converting milliliters back to fluid ounces

To reverse the conversion, divide the milliliters by 29.5735. This is exactly why a 500 mL water bottle is often labeled 16.9 fl oz: 500 ÷ 29.5735 works out to about 16.9 U.S. fluid ounces. A 1-liter bottle (1,000 mL) is close to 33.8 fluid ounces.

Quick reference for common container sizes

These everyday sizes cover most of the conversions you will run into:

• Single shot: about 1.5 fl oz = 44 mL
• Small coffee: 8 fl oz = about 237 mL
• Soda can: 12 fl oz = about 355 mL
• Standard water bottle: 16.9 fl oz = 500 mL
• Large bottle: 33.8 fl oz = about 1 liter

Fluid ounces vs dry ounces

It is worth repeating that a fluid ounce measures volume, while a plain ounce measures weight, and the two are not interchangeable. A fluid ounce of water happens to weigh close to one weight ounce, but a fluid ounce of honey or oil weighs a different amount, because weight depends on the liquid's density. When a label or recipe just says "oz," check whether it means fluid ounces or weight ounces before you convert.

Fluid ounces in cups, pints, quarts, and gallons

Fluid ounces also stack up neatly into the larger U.S. volume units, which helps when a recipe jumps between them:

• 1 cup = 8 fluid ounces = about 237 mL
• 1 pint = 16 fluid ounces = about 473 mL
• 1 quart = 32 fluid ounces = about 946 mL
• 1 gallon = 128 fluid ounces = about 3.79 liters

FAQs About Fluid Ounces to Milliliters

Sources

Related converters