Carry-on bags have no weight limit, but liquids are capped at 3.4 ounces per container
The Transportation Security Administration (TSA) does not restrict how many ounces your carry-on bag itself can weigh. You can bring a bag that weighs 50 pounds if you want — the airline may reject it at the gate for being too large, but TSA has no ounce or pound rule for the bag itself.
The 3.4-ounce rule applies only to liquids, gels, and aerosols. Each container must hold 3.4 ounces (100 millilitres) or less. All containers go into a single quart-sized clear plastic bag. Solid items — clothing, electronics, books, food — have no ounce limit at TSA checkpoints.
Airlines do set their own size and weight limits for carry-on bags, and these vary by carrier. American Airlines, Delta, United, and Southwest all allow bags up to 22 inches long, 14 inches wide, and 9 inches deep, but they do not publish a weight ceiling. If your bag is within those dimensions and you can lift it into the overhead bin without help, you are within policy on most major carriers.
Key Takeaways
- TSA does not weigh carry-on bags or set an ounce limit for them, only for the liquids inside.
- Liquids, gels, and aerosols are limited to 3.4 ounces per container, and all containers must fit in one quart-sized bag.
- Airlines set their own size limits for carry-on bags, typically 22 by 14 by 9 inches, but do not publish weight limits.
- Solid foods, clothing, and electronics have no ounce restrictions at security or on the plane.
What counts as a liquid under the 3.4-ounce rule
The TSA defines liquids broadly. Obvious ones include water, juice, yogurt, peanut butter, and honey. Less obvious ones are toothpaste, shampoo, conditioner, lotion, sunscreen, deodorant, mascara, and lip gloss. Aerosol cans — spray deodorant, spray sunscreen, hairspray — also count, even if they are not technically liquid.
Solid foods pass through security with no ounce limit. A block of cheese, a sandwich, an apple, or a container of cookies can be any weight. The line between solid and liquid is where TSA draws the boundary. If it spreads or pours, it counts as a liquid. If it holds its shape, it does not.
Medications in liquid or gel form follow the same 3.4-ounce rule, but you can bring more than one container if you have a medical reason. Bring a doctor's note or the prescription label if the amount seems large. Powders — including protein powder, baby formula, and flour — are treated as solids and have no ounce limit, though TSA may open and test them at the checkpoint.
How to pack liquids to pass through security
All liquids, gels, and aerosols must go into a single quart-sized clear plastic bag. The bag itself must be clear so TSA officers can see inside without opening it. Each container inside the bag must be 3.4 ounces or smaller. You cannot bring one 5-ounce bottle of shampoo, even if you have room in the bag.
Remove the bag from your carry-on before you reach the security line and place it in a bin on the conveyor belt. Do not wait until the officer asks — having it ready speeds up the process. After security, you can return the bag to your carry-on.
If you forget to pack liquids in the bag or bring a container larger than 3.4 ounces, TSA will confiscate it. You cannot argue your way past this rule. If you need a product after security, buy it in the airport terminal — prices are higher, but the items are legal to bring on the plane.
Airline carry-on size and weight policies
Most major U.S. airlines allow one carry-on bag and one personal item (purse, backpack, or laptop bag). The carry-on bag limit is usually 22 by 14 by 9 inches. A few airlines are stricter: Spirit and Frontier charge for carry-on bags that do not fit their smaller dimensions (21 by 13.5 by 8.5 inches).
Airlines do not publish weight limits for carry-on bags, but they do enforce a practical rule: if you cannot lift it into the overhead bin yourself, it is too heavy. Gate agents may ask you to gate-check a bag if it appears too large or heavy, and you will not be charged, but you will not have access to it during the flight.
Check your specific airline's website before you pack. Some carriers have different rules for different cabin classes, and regional airlines sometimes have stricter limits than major carriers. The airline's baggage page will show the exact dimensions and any weight guidance.
What happens if your bag is too heavy or too large
If your carry-on bag exceeds the airline's size limit, a gate agent will ask you to check it at the gate. This is free — you will not pay a baggage fee. Your bag will be loaded into the cargo hold and returned to you at your destination airport. You will not have access to it during the flight.
If your bag is within size limits but appears very heavy, an agent may ask you to weigh it or may straightforward ask you to gate-check it. There is no formal weight threshold, so this is at the agent's discretion. Packing lighter and distributing weight evenly makes it less likely an agent will question your bag.
Liquids that exceed 3.4 ounces per container or that do not fit in your quart-sized bag will be thrown away at security. There is no option to check them or to repack them. If you need a large bottle of something, pack it in your checked luggage instead — checked bags have no liquid restrictions.
Packing strategies to stay within limits
Buy travel-sized bottles of toiletries before your trip, or transfer products into small containers. Many drugstores sell empty 3.4-ounce bottles designed for this purpose. Label them clearly so you know what is inside.
If you are traveling for more than a few days and need full-sized bottles, pack them in checked luggage. Checked bags allow unlimited liquids, so a gallon of shampoo is fine in your suitcase — just not in your carry-on.
For short trips, buy toiletries at your destination instead of packing them. Airport and hotel shops sell shampoo, deodorant, and other basics, though at higher prices. This eliminates the need to pack liquids altogether and saves carry-on space.
International carry-on liquid rules
Most countries outside the United States follow the same 3.4-ounce (100-millilitre) liquid rule. The European Union, Canada, Australia, and the United Kingdom all use this standard. If you are flying internationally, assume the 3.4-ounce limit applies unless your airline states otherwise.
Some countries have additional restrictions on specific items. For example, certain countries limit the amount of alcohol you can bring, or restrict aerosols. Check your destination country's aviation authority website or ask your airline before you pack.
If you are connecting through another country, remember that you will go through security again at the connection point. Any liquids you bought after your first security checkpoint will be confiscated at the second one. Buy liquids only after your final security screening, or pack them in checked luggage.
Frequently Asked Questions
Can I bring a full-sized water bottle in my carry-on?
No, not through security. Water is a liquid and is limited to 3.4 ounces per container. You can bring an empty water bottle through security and fill it at a water fountain or refill station after you pass the checkpoint. Many airports have free refill stations near gates.
Do I have to put my carry-on bag on a scale?
No. TSA does not weigh carry-on bags. Airlines do not weigh them either unless an agent suspects it is too heavy to lift safely. If you can comfortably put your bag in the overhead bin, you are within policy.
What if I have a medical liquid that is more than 3.4 ounces?
Bring a doctor's note or prescription label. TSA allows larger quantities of medically necessary liquids, but you must declare them at security and show documentation. Insulin, for example, is allowed in any amount if you have proof it is prescribed to you.
Can I bring solid food in my carry-on?
Yes. Sandwiches, fruit, cheese, nuts, and other solid foods have no ounce limit and do not need to go in the quart-sized bag. Peanut butter and honey are gels, so they count as liquids and are limited to 3.4 ounces.
Do I need to remove my carry-on bag from the conveyor belt at security?
No. Your carry-on bag goes through the X-ray machine on the conveyor belt. Only the quart-sized liquid bag needs to be removed and placed in a bin. Your carry-on will come out the other side of the X-ray machine and you will collect it after you pass through the metal detector.