Liquids, Gels & Aerosols: TSA Rules for Carry-On Bags
TSA 3-1-1 rule explained. What liquids, gels, and aerosols you can bring through airport security in carry-on and checked bags.
The 3-1-1 Rule
3.4 ounces (100ml) — maximum container size for carry-on liquids
1 quart-sized bag — all liquid containers must fit in one clear, resealable bag
1 bag per passenger — each traveler gets one liquids bag
Exceptions to the Liquids Rule
Medically necessary liquids, baby formula, breast milk, and medications in quantities exceeding 3.4 ounces are permitted but must be declared at the checkpoint.
The rule applies to anything you could pour, spread, spray, or squeeze — including toothpaste, sunscreen, peanut butter, and aerosols. Container size is what counts, not how full it is. Anything larger goes in checked baggage, and liquids bought past the checkpoint have no size limit at all.
How liquids are screened at the checkpoint
Pack the quart bag last — Keep your liquids bag in an outer pocket or at the top of your carry-on so you can pull it out without unpacking the whole bag at the belt.
Place the bag in its own bin — In standard lanes the quart bag comes out of your luggage and goes flat in a bin, next to your laptop. TSA PreCheck lanes usually let liquids stay in the bag.
Declare anything oversized — Tell the officer before your bag enters the X-ray if you are carrying medically necessary liquids, formula, breast milk, or juice for a toddler. These are screened separately and do not need to fit the quart bag.
Expect a secondary check — Oversized or dense liquids may be opened, vapor-tested, or run through a bottle scanner. This is routine and does not mean the item is prohibited.
Repack past the checkpoint — Once cleared you can refill an empty bottle at a fountain and buy any size of liquid airside — post-security purchases are not subject to 3-1-1.
Carry-on liquids checklist
Goes in the quart bag
Shampoo, conditioner, and body wash in 3.4 oz travel bottles
Alcohol between 24% and 70% ABV, capped at 5 liters per passenger
Common liquids mistakes
Assuming a half-empty 8 oz bottle is fine — the printed container size is what counts, not how much is left inside.
Using a gallon bag instead of a quart bag. Officers can require you to downsize on the spot.
Forgetting that peanut butter, hummus, yogurt, and honey are treated as liquids.
Leaving aerosol dry shampoo or hairspray loose in a carry-on rather than in the quart bag.
Packing lithium-battery electric toothbrushes or razors in checked bags with liquids instead of carry-on.
Frequently Asked Questions
Can I bring a water bottle through TSA security?
Empty water bottles are allowed through TSA security checkpoints. You can fill them at water fountains or bottle-filling stations after clearing security.
Does toothpaste count as a liquid for TSA?
Yes, toothpaste is classified as a paste and falls under the TSA 3-1-1 liquids rule. It must be in a container of 3.4 ounces (100ml) or less.
Can I bring shampoo on a plane in my carry-on?
Shampoo is allowed if it's in a container of 3.4 ounces (100ml) or less and fits in your quart-sized liquids bag. Solid shampoo bars are not subject to liquid rules.
Is deodorant a liquid according to TSA?
Gel, spray, and roll-on deodorants are classified as liquids and must follow the 3-1-1 rule. Solid stick deodorant is not considered a liquid.
Can I bring contact lens solution through airport security?
Yes. Contact lens solution is considered a medically necessary liquid and may exceed the 3.4-ounce limit. Declare it to a TSA officer at the checkpoint.