A small toiletry bag can save a surprising amount of time at a US airport checkpoint. The Transportation Security Administration's 3-1-1 rule sets limits for ordinary liquids, gels and aerosols in carry-on baggage. The rule is about each container's capacity as well as the bag holding it, so a nearly empty large bottle is not the same as a small travel bottle.
This guide covers TSA screening in the United States. Airlines also have baggage size and weight rules, and security rules can differ at airports outside the US. Check the airport and airline requirements for each departure, especially if a trip includes a connection or return flight abroad.
Read 3-1-1 as three separate checks
TSA's checklist says ordinary carry-on liquids, gels and aerosols must be in containers of 3.4 ounces (100 milliliters) or less. They must fit in one clear, quart-size, zip-top plastic bag, with one such bag per passenger. The size printed on the container matters: a 6-ounce bottle with only a little lotion left still exceeds the ordinary container limit.
Make a pile of items that pour, spread, spray or have a gel-like consistency. Toothpaste, lotion, liquid makeup and similar products belong in the planning exercise. Check the capacity on each package. When the bag is full, close it comfortably rather than counting only the individual bottle sizes. Keep it accessible for screening if an officer asks you to remove it.
Decide what belongs in the carry-on
- Put a small, clearly labeled portion of essential toiletries in qualifying containers.
- Place larger ordinary containers in checked baggage if the airline and relevant safety rules allow them.
- Consider solid alternatives where they meet your needs, but check TSA's item guidance for uncertain products.
- Leave space for a purchase you may need to carry through a later checkpoint.
Checked baggage is not a universal solution: separate restrictions can apply to aerosols, hazardous materials and other items. Liquids may leak under travel conditions, so close caps securely and protect clothing. For short trips, a small quantity can be easier to pack than transferring everything you own. Label refillable containers so you can identify their contents and keep original instructions when they matter.
Separate medically necessary liquids
TSA permits medically necessary liquids in reasonable quantities above the standard limit, subject to screening. Tell the officer at the start of screening and separate these items from other belongings. Additional screening may be required. Check TSA's current guidance for your specific medicine, equipment or circumstances before travel, and allow time for the process.
Carry medication you need access to during the journey in your carry-on when practical. Keep it identifiable and consider bringing its prescription information, while checking applicable destination laws and airline requirements. This packing advice does not replace instructions from your prescriber. If you are uncertain about a particular item or screening procedure, contact TSA in advance.
Prepare for the checkpoint
Start with an empty bag so an overlooked item does not become a problem. Put the liquids bag where you can reach it without unpacking your entire case. Follow the officer's instructions: screening equipment and procedures can vary by airport and lane. An officer may require additional inspection, and the final decision on an item's passage rests with TSA.
If something is not allowed, available options depend on the checkpoint and time you have. You might return it to a companion, check it if permitted, or surrender it. Avoid relying on a last-minute workaround, particularly when the item is expensive or necessary. Arriving with time to resolve a question can make the experience less stressful.
Check the whole itinerary
Duty-free liquids and connections can involve additional rules, packaging and documentation. Review current TSA and airline guidance before buying anything you expect to bring through another checkpoint. Rules elsewhere may differ, even on the return leg of the same trip.
The night before departure, look at the labels, close the quart bag and put it in an accessible pocket. Then check your medication and any unusual item separately. A small packing review is more useful than discovering at the belt that a favorite full-size bottle cannot travel in the cabin. Keep the bag near the top of your carry-on and leave yourself time to follow the instructions at your particular lane. If you travel with someone else, each traveler should arrange their own eligible liquids bag and keep essential items readily identifiable.
The readable TSA bulletin linked below is dated 16 May 2019. Its liquid-medication explanation supports the general distinction described here. Some current TSA pages restricted automated access during research; consult TSA directly for the latest requirements and your specific items before traveling.