The U.S. Transportation Security Administration (TSA) restricts liquids in carry-on luggage to containers no larger than 3.4 ounces (100 milliliters), all fitting inside a single clear quart-sized bag. This rule applies to all passengers boarding domestic and international flights departing from U.S. airports.
Liquids include water, shampoo, lotion, toothpaste, perfume, and even gels like hair gel or face cream. The rule exists to limit the amount of liquid explosive material that could be brought onto aircraft. The 3.4-ounce limit helps even if someone attempted to use a liquid substance as a weapon, the quantity would be too small to cause significant harm.
Passengers may bring multiple containers as long as each is under 3.4 ounces and all fit within one transparent, resealable quart-sized bag. The bag must be placed in a bin during screening and removed from your carry-on before going through the X-ray machine. Failure to comply results in removal of the bag and potential delay at the checkpoint.
At airport security checkpoints, TSA agents screen all carry-ons using X-ray machines. Liquids are flagged if they exceed the 3.4-ounce threshold or if they're not contained in a clear bag. Even if your container is under 3.4 ounces, placing it in a non-transparent bag or carrying it loose can trigger a manual inspection.
For example, a traveler bringing a 4-ounce bottle of hand sanitizer will be asked to discard it or place it in checked baggage. A 2-ounce travel-sized shampoo bottle fits, but if it's in a dark-colored bag, the agent may still require it to be removed for inspection.
After passing through the checkpoint, passengers may refill their liquids at a restroom or airport kiosk. However, they cannot re-enter the secure area with large quantities unless they purchase them after screening.
The TSA defines liquids broadly. Items such as:
These all fall under the 3.4-ounce rule. Solid forms of these products-like solid soap or wax-based deodorant-are exempt.
| Type of Item | Allowed Size | Container Requirement |
|---|---|---|
| Shampoo | ≤3.4 oz (100 mL) | Clear, resealable bag |
| Toothpaste | ≤3.4 oz | Must be in bag |
| Perfume | ≤3.4 oz | Bag required |
| Medication (liquid) | Unlimited, if needed | Must be declared |
| Alcohol (over 70% ABV) | Not allowed in carry-on | Must be checked |
Travelers with medical needs may bring larger quantities of liquid medications. These must be declared at the checkpoint and may be subject to additional screening. The TSA allows reasonable amounts based on the duration of the trip and medical necessity.
Many travelers assume that "liquids" only refer to water or drinks. In reality, the TSA includes gels, pastes, and semi-solids. A 3.4-ounce tube of toothpaste counts as a liquid-even though it's not wet. Similarly, a jar of face cream that spreads easily is treated the same way.
A frequent error is using a bag that isn't transparent. Even if the bag holds all containers under 3.4 ounces, a dark or opaque bag will trigger a secondary inspection. The bag must be see-through so agents can verify contents quickly.
Another misconception is that the rule applies only to international flights. It applies to all domestic and international flights departing from U.S. airports. Travelers flying from Canada, Mexico, or Europe to the U.S. must follow the same rules upon arrival.
Consider a traveler flying from Los Angeles to New York with a carry-on bag. They pack:
All items are placed in a single clear quart-sized bag. The bag is sealed and placed in a bin. As the bag passes through the X-ray machine, the image shows labeled containers under 3.4 ounces. The agent approves the bag and allows the passenger to proceed.
If the same traveler had packed a 6-ounce bottle of lotion in a black ziplock bag, the agent would stop the bag for inspection. The passenger would be asked to remove the item and either discard it or check it. This causes delays and increases stress at the checkpoint.
Items that are solid at room temperature are not subject to the liquid rule. Examples include:
Even if a product melts in heat, it's still classified by its state at room temperature. A solid chocolate bar is allowed in carry-on. A liquid-filled chocolate truffle is not.
Some travelers confuse the TSA's liquid limits with dietary rules like a liquid fast. A liquid fast involves consuming only liquids such as water, broth, or juice for health reasons. This is unrelated to airport security policies.
In 2022, I flew with a carry-on containing a 4-ounce bottle of lotion in a dark blue bag. The agent stopped my bag for inspection. I was asked to remove the lotion and declare it. After confirming it was for personal use, I was allowed to proceed-but only after waiting 15 minutes while the agent verified the contents.
This delay could have been avoided by using a clear bag and staying under 3.4 ounces. The incident reinforced how strict enforcement is-even for minor violations.
What are liquid limits on flights? They are standardized restrictions enforced by the TSA to improve air travel safety. All liquids in carry-on bags must be ≤3.4 ounces and fit in one clear, resealable quart-sized bag. Non-compliance leads to delays, confiscation, or refusal to board.
Always double-check your carry-on before reaching security. Use travel-sized containers and a transparent bag. When in doubt, pack larger quantities in checked luggage.
Understanding what are liquid limits on flights prevents stress and ensures a smooth process through airport security.