You can bring liquids in containers of 3.4 ounces (100 milliliters) or less each in your carry-on luggage on a plane. All these containers must fit comfortably within one clear, resealable quart-sized (about 32 ounces) plastic bag. Each passenger is allowed only one such bag

. This is commonly known as the TSA's "3-1-1 rule":

• 3.4 ounces (100 ml) or less per container
• 1 quart-sized clear plastic bag
• 1 bag per passenger

In total, this means you can carry roughly 25 to 32 ounces of liquids in your carry-on, depending on how many 3.4-ounce containers fit into the quart bag

. There are some exceptions to this rule:

• Medically necessary liquids (like prescription medications, baby formula, breast milk) can be carried in larger amounts but must be declared and screened separately

• Liquids purchased after passing through airport security (duty-free or airport shops) are not subject to the 3.4-ounce limit if kept in the sealed, original packaging with receipt

• Larger containers of liquids must be packed in checked baggage.

These rules are consistent with international regulations, including those in Europe, where the maximum per container is also 100 ml (about 3.38 ounces)

. In summary, for carry-on luggage, you are limited to liquids in containers of 3.4 ounces or less, fitting all containers into one quart-sized bag per passenger. Larger amounts must go in checked bags or qualify under specific exceptions.