You can bring liquids, aerosols, gels, creams, and pastes in carry-on luggage on a plane only if each container is 3.4 ounces (100 milliliters) or less. All these containers must fit into one clear, quart-sized, resealable plastic bag, and each passenger is allowed only one such bag

. In terms of total volume, since the quart-sized bag holds about 32 ounces, you can typically carry around seven to eight containers of 3.4 ounces each, which sums to roughly 25 ounces of liquids in your carry-on

. There are exceptions for medically necessary liquids, baby formula, breast milk, and medications, which may exceed the 3.4-ounce limit but must be declared and presented separately during security screening

. Liquids purchased after passing through airport security, such as duty-free items, are not subject to these limits if they remain sealed in their original packaging with a receipt

. For checked baggage, there are generally no TSA liquid size restrictions, but airline and international regulations may apply

. Summary:

• Maximum size per liquid container in carry-on: 3.4 ounces (100 ml)
• All containers must fit in one quart-sized clear bag
• One bag per passenger
• Total liquid volume in carry-on roughly 25–32 ounces depending on container sizes
• Exceptions for medications, baby formula, breast milk (must declare)
• Duty-free liquids purchased after security can exceed limits if sealed
• No size limits for liquids in checked baggage

This is known as the TSA 3-1-1 rule and is standard for flights departing from or within the United States and many international flights