TSA 3-1-1 Liquids Rule: How Many Ounces Can You Bring?

Where these numbers come from

The 3-1-1 rule is easy to remember once you split it: 3.4 ounces, one bag, one bag per traveler. Every liquid, gel, cream, paste or aerosol in your carry-on must sit in a container of 3.4 ounces (100 milliliters) or less. All of those containers go together in a single clear quart-size bag.

The limit applies to the container, not to what is left inside. A 6-ounce tube holding one ounce of product is still a 6-ounce tube in the eyes of most screeners. Five 3.4-ounce bottles add up to 17 ounces of liquid, and that is fine, because the rule caps each container rather than the total. The real ceiling is how many fit in the bag with the zipper closed.

Checked bags work differently. TSA does not cap liquids there, but federal hazmat rules do for toiletries and aerosols: no more than 18 ounces per container and 70 ounces in total per person, with spray nozzles capped. Two full-size 16-ounce shampoos and a 12-ounce can of hair spray total 44 ounces, well inside the 70-ounce allowance. Flammable non-toiletry aerosols such as spray paint are banned in both bags.

Recent news has blurred the picture. TSA dropped its shoe-removal requirement in July 2025, but the liquids rule was left alone, and TSA has given no date for ending it. Some airports with newer CT scanners may be more relaxed in practice. Do not count on it. Pack to the written rule and treat any leniency as a bonus.

Outside the US the picture is patchy. As of June 2026, Heathrow, Gatwick, Dublin and several Italian airports allow up to 2 liters at checkpoints with new scanners, while Paris, Madrid, Lisbon and Athens still enforce 100 ml. A flight back to the US is screened to TSA standards regardless. If your itinerary has a connection, pack for the strictest airport. See the liquids 3-1-1 checker to test a bag, or the baby formula page and medications page for the main exceptions.

One narrow exception: international duty-free liquids bought abroad before a connecting flight to the US can travel in a sealed, tamper-evident bag with a receipt dated within 48 hours. They still get screened, and opening the bag voids the exemption.

Sources

• TSA liquids rule (3-1-1)
• FAA PackSafe medicinal and toiletry articles
• TPG: status of the 3-1-1 rule and the July 2025 shoe policy
• GOV.UK hand luggage liquids
• TNT Magazine: Europe carry-on liquids rules, June 2026

Figures checked on September 30, 2026.

This page is general information, not legal, insurance or travel-agent advice. Fees, rules and limits change, so confirm the figures with the official sources listed above before you book or travel.