The TSA 3-1-1 liquid rule limits you to 3.4 ounces per container

The TSA allows liquids, gels, creams, and pastes through security checkpoints only if each container holds 3.4 ounces (100 milliliters) or less. This is the single rule that matters for most travelers. All containers must fit inside a single quart-sized clear plastic bag, and you can bring one bag per person.

The 3.4-ounce limit applies to the container size, not how full it is. A half-empty 3.4-ounce bottle is allowed. A 4-ounce bottle is not, even if it contains only 2 ounces of liquid.

This rule applies to carry-on bags only. Liquids in checked luggage have no ounce limit, though airlines may have their own restrictions on hazardous materials.

Key Takeaways

  • Each liquid container in your carry-on must be 3.4 ounces (100 milliliters) or smaller.
  • All liquid containers must fit inside one quart-sized clear plastic bag, which you remove at security.
  • Liquids include shampoo, conditioner, lotion, toothpaste, peanut butter, yogurt, and anything that flows or spreads.
  • Powders in containers larger than 12 ounces may be opened and tested at security, so pack them in checked bags when possible.
  • Checked baggage has no ounce limit for liquids, but hazardous materials like paint or fuel are banned entirely.

What counts as a liquid under TSA rules

The TSA defines liquids broadly: anything that flows, spreads, or is pourable. This includes obvious items like water, juice, and shampoo, but also toothpaste, deodorant, peanut butter, yogurt, honey, and jam. Aerosols like hairspray and sunscreen spray also count as liquids.

Solid items like lipstick, solid deodorant, and dry powder do not count as liquids. A stick of deodorant can be any size. Powders are treated differently — see the section below.

If you are unsure whether something is a liquid, the safest approach is to pack it in your checked bag or buy it after you pass through security.

How powders are handled at security

Powders in containers larger than 12 ounces may be opened and tested at the security checkpoint. This includes protein powder, flour, powdered sugar, baby formula, and makeup powder. The TSA uses a swab test to check for explosives residue.

Powders 12 ounces or smaller can go through carry-on without testing, though TSA officers can still inspect them if they choose. To avoid delays, pack powders larger than 12 ounces in your checked bag instead.

If you are traveling with baby formula or medication powder, inform the TSA officer before screening begins. These items receive different handling and do not count against your liquid allowance.

Building your quart-sized bag correctly

You need one clear, quart-sized plastic bag — the kind that measures roughly 7 inches by 8 inches. You can buy these at any drugstore, or TSA checkpoints sometimes have them available. Remove this bag from your carry-on and place it in the security bin before you reach the scanner.

Every liquid container must fit inside the bag with the bag still closable. If a 3.4-ounce bottle does not fit, you cannot bring it. Pack strategically: put heavier items on the bottom and arrange bottles so nothing shifts during travel.

You are allowed one bag per person. If you travel with a partner or child, each person gets their own bag.

Exceptions and special items

Medications in liquid or gel form are exempt from the 3.4-ounce limit, but you must declare them to the TSA officer and keep them separate from your quart bag. Bring the original labeled container so the officer can see the medication name and your name.

Baby formula, breast milk, and juice for infants also bypass the 3.4-ounce rule. You do not need to pack them in the quart bag. Tell the officer you are traveling with these items before screening.

Frozen items like ice packs are allowed in carry-on if they are completely solid when you reach the checkpoint. If they have begun to thaw and are slushy or liquid, they count as liquids and must follow the 3.4-ounce rule.

What happens if you pack liquids incorrectly

If you arrive at security with liquids that exceed 3.4 ounces or that do not fit in your quart bag, TSA officers will not let them through. You have three options: throw the item away, go back to check your bag if you have time, or mail it to your destination.

This is not a fine or violation — it is straightforward a security rule. Officers are not trying to confiscate your belongings; they are following federal aviation safety rules. Arriving early gives you time to handle this without missing your flight.

Liquids in checked baggage

Checked bags have no ounce limit for liquids. You can pack full-sized bottles of shampoo, lotion, or any other liquid without restriction. However, some hazardous materials are banned from checked bags entirely, including paint, fuel, certain cleaning products, and some types of batteries.

If you are unsure whether a liquid is allowed in checked baggage, check the TSA website or ask at the airline counter before you check your bag. Most everyday toiletries and food items are fine.

Keep in mind that checked bags can leak during handling. Pack liquids in a separate plastic bag inside your checked luggage to protect your other belongings.

Frequently Asked Questions

Can I bring a full-sized bottle of shampoo if I check my bag?

Yes. Checked baggage has no ounce limit for liquids like shampoo, conditioner, lotion, or other toiletries. Pack it in a plastic bag inside your checked luggage to prevent leaks from damaging your clothes.

What if my medication is a liquid larger than 3.4 ounces?

Liquid medications are exempt from the 3.4-ounce limit. Keep the original labeled container and declare it to the TSA officer before screening. Pack it separately from your quart bag.

Do I need to remove my quart bag from my carry-on at security?

Yes. Remove the quart bag and place it in the security bin before you go through the scanner, just like you would with shoes or a belt. The officer will screen it separately.

Can I bring peanut butter through TSA security?

Peanut butter is a spread and counts as a liquid. If your container is 3.4 ounces or smaller, it can go in your quart bag. Larger containers must be packed in checked baggage.

What if I buy a liquid after I pass through security?

Liquids purchased after you pass through security can be any size and do not need to follow the 3.4-ounce rule. You can bring them on the plane in your carry-on or checked bag.