The 3.4-ounce liquid rule is the main limit TSA enforces

TSA allows you to bring liquids, gels, and aerosols in containers of 3.4 ounces (100 millilitres) or smaller through security. Each container must be 3.4 ounces or less — a 3.5-ounce bottle will be confiscated. All containers go into a single quart-sized clear plastic bag, and you remove that bag from your carry-on when you reach the scanner.

This rule applies to carry-on bags only. You can pack full-size bottles of liquids in checked luggage with no ounce limit, though some airlines have their own restrictions on hazardous materials.

The rule covers anything that flows, spreads, or sprays: shampoo, conditioner, lotion, toothpaste, peanut butter, yogurt, jam, honey, hummus, soup, and cologne. Solid foods like granola bars, cheese, and apples have no ounce limit in carry-on or checked bags.

Key Takeaways

  • Each liquid, gel, or aerosol container in your carry-on must be 3.4 ounces (100 ml) or smaller.
  • All containers together go into one quart-sized clear plastic bag, which you remove at security.
  • Full-size bottles are allowed in checked luggage with no ounce restriction.
  • Solid foods and powders over 12 ounces may require additional screening but are not automatically banned.
  • Some items like medications and baby formula have different rules and do not count toward the liquid limit.

What counts as a liquid under the 3.4-ounce rule

TSA defines liquids broadly. The category includes obvious ones like water, juice, and milk, but also anything with a pourable or spreadable consistency: yogurt, peanut butter, jam, honey, hummus, salsa, and sour cream. Aerosols like deodorant, hairspray, and sunscreen spray count too. Gels include toothpaste, hair gel, and aloe vera gel.

The test is whether the substance flows or spreads at room temperature. If you are unsure, assume it is a liquid. TSA officers at the checkpoint make the final call, and they can confiscate items they judge to be liquids even if you thought they were solid.

Powders over 12 ounces may be opened and tested at security, but they are not subject to the 3.4-ounce limit. Solid foods like bread, fruit, and chocolate are not restricted by ounce.

How to pack liquids in your carry-on bag

Buy or bring a clear quart-sized plastic bag — the standard gallon freezer bag is too large. Place all your 3.4-ounce-or-smaller containers inside it. Seal the bag. When you reach the security checkpoint, remove the bag from your carry-on and place it in the bin before you go through the scanner.

Do not mix containers of different sizes in hopes of staying under the limit. A 5-ounce bottle is a 5-ounce bottle, even if you only plan to use 3.4 ounces of it. TSA measures the container size, not how full it is.

If you forget to pack liquids in the bag or bring a container larger than 3.4 ounces, you will be asked to throw it away or check it. You cannot go back through security after you have passed the checkpoint.

Medications, baby formula, and other exceptions

Prescription and over-the-counter medications in liquid form do not count toward the 3.4-ounce limit. You can bring full bottles of liquid medication in your carry-on. Bring the medication in its original labeled container if possible.

Baby formula, breast milk, and baby food are also exempt from the 3.4-ounce rule. You can bring as much as you need for your flight in your carry-on. Tell the TSA officer at security that you have these items so they can screen them separately if needed.

Frozen liquids like ice packs are allowed in carry-on bags only if they are completely frozen solid when you go through security. Once they begin to thaw, they are treated as liquids and must follow the 3.4-ounce rule.

What happens if you bring a container that is too large

If a TSA officer finds a liquid container larger than 3.4 ounces in your carry-on, they will confiscate it. You cannot open it, use some of it, and keep the rest. The entire container is removed.

You have a few options at that point: throw it away, go back through the airport to check it in a checked bag (if you have time and your airline allows it), or leave it with a friend or family member who is not traveling. Most people throw it away rather than delay their flight.

This is why many travelers buy travel-size bottles before a trip or wait to buy full-size items at their destination. Some airports have shops past security where you can buy liquids after you have cleared the checkpoint.

Checked baggage has no ounce limit for liquids

You can pack full-size bottles of shampoo, lotion, cologne, and other liquids in checked luggage with no ounce restriction. The TSA does not limit ounces for checked bags — only for carry-on.

Your airline may have restrictions on hazardous materials like flammable liquids, so check your airline's baggage policy before packing. Most airlines allow normal toiletries and cosmetics in checked bags without issue.

If you are checking a bag, pack liquids in a separate compartment or plastic bag in case a container leaks. A broken bottle of shampoo can ruin clothes and other items in your luggage.

International flights and different country rules

The 3.4-ounce rule applies to flights departing from the United States, including international flights leaving U.S. airports. If you are flying from another country, that country's security rules explore instead — some are stricter, some are looser.

If you are connecting through a U.S. airport on an international flight, you will go through U.S. security and must follow the 3.4-ounce rule for your carry-on. If you are connecting from a U.S. flight to an international flight at a foreign airport, you will go through that airport's security with its own rules.

When in doubt, pack all liquids in checked luggage for international travel. It is simpler than learning each country's rules and removes the risk of losing items at security.

Frequently Asked Questions

Can I bring a 3.4-ounce container that is completely full?

Yes. The rule is 3.4 ounces or smaller, so a full 3.4-ounce container is allowed. A 3.5-ounce container is not, even if it is mostly empty. TSA measures the container size, not the amount of liquid inside.

Do I need to remove my liquids bag if I have TSA PreCheck?

No. TSA PreCheck members can leave liquids in their carry-on bag and do not need to remove shoes, belts, or light jackets. You still cannot bring containers larger than 3.4 ounces.

What if my toothpaste or shampoo does not have an ounce label?

Check the back or bottom of the container for millilitres (ml). 100 ml equals 3.4 ounces. If there is no label at all, measure it or assume it exceeds the limit and pack it in checked luggage instead.

Can I bring a full water bottle through security?

No. Water is a liquid and must follow the 3.4-ounce rule. You can bring an empty water bottle through security and fill it at a water fountain or bottle-filling station past the checkpoint. Many airports have these stations near gates.

Are solid deodorants allowed in carry-on bags?

Yes. Solid stick deodorant is not a liquid and has no ounce limit. Deodorant spray or gel counts as a liquid or aerosol and must be 3.4 ounces or smaller.