TSA questions and answers are most useful before you pack: a familiar item may be treated differently at a checkpoint depending on whether it is a liquid, a spare battery, a medical supply or a sharp object. For U.S. airport screening, use TSA’s current “What Can I Bring?” lookup tool to check individual items, and follow the instructions given by officers at the checkpoint. The standard liquids limit is a good baseline, but exceptions and screening procedures can vary. Also distinguish TSA security rules from your airline’s baggage limits, which determine matters such as bag size and whether you can check luggage.
The answer depends on the item and sometimes on how it is packed. TSA screens items for security; the airline sets its own baggage allowance, including size and weight limits. A bag may meet TSA security rules but still be too large for your airline’s cabin-bag policy.
| Item or concern | General screening guidance | What to check before travel |
|---|---|---|
| Toiletries and other liquids | For standard carry-on screening, containers should be 3.4 ounces (100 milliliters) or less and fit in one quart-size bag. | Confirm whether an item counts as a liquid, gel, cream or paste. Pack larger containers in checked baggage if permitted. |
| Prescription and medical supplies | Medications and medically necessary liquids may be subject to screening outside the standard liquids limit. | Tell the officer about these items and check arrangements for medical devices or supplies. |
| Food | Solid foods are generally easier to carry through screening than foods with a liquid, gel or spreadable consistency. | Check the liquids rule for items such as yogurt, sauces, dips and spreads. |
| Power banks and spare batteries | Spare lithium batteries and power banks should be packed in carry-on baggage. | Check battery limits with your airline, especially for high-capacity batteries or unusual devices. |
| Knives and other sharp objects | Knives are not permitted in carry-on baggage. Other sharp items may have their own restrictions. | Look up the exact item. If it is allowed in checked baggage, protect it from injuring baggage handlers or inspectors. |
| Firearms | Firearms are not allowed in carry-on baggage. They must follow TSA and airline procedures for checked baggage. | Check the current rules for declaration, cases, ammunition and laws at your destination. |
For standard carry-on screening, each liquid container must hold no more than 3.4 ounces (100 milliliters), and the containers must fit in one quart-size bag. This applies to many toiletries and to products that might not seem like drinks, including gels, creams, pastes and spreadable foods. A partly empty oversized bottle does not meet the standard based on the amount of liquid left inside; the container itself is larger than the permitted size.
Put larger containers in checked baggage when the item is allowed there, or buy a permitted size before you travel. Do not assume that a checkpoint’s equipment or a previous trip’s experience means you can bring larger liquids through. Screening procedures can differ, so use the standard limit unless TSA’s current guidance confirms an exception for your item or airport.
Empty reusable bottles can generally pass through screening and be filled afterward. If you bring a bottle containing water or another drink, treat it as a liquid and plan around the standard carry-on limit.
Medication is permitted through security, and medically necessary liquids can be handled differently from ordinary toiletries. Keep medicines and supplies easy to reach, and tell the TSA officer about them before screening. They may need separate inspection. Allow extra time if you rely on a medical device or carry supplies that require explanation.
For equipment such as mobility aids or devices containing batteries, check the TSA guidance for the specific item and ask your airline about handling or stowage. Airline procedures can affect how equipment is transported even when the item is permitted through security. If you need assistance during screening because of a disability or medical condition, TSA Cares can provide information about the screening process; contact TSA in advance to ask what support is available for your circumstances.
Keep essential medication in your carry-on rather than relying on checked baggage. That way, it remains accessible during the journey, and you can explain what it is if an officer needs to inspect it. For travel outside the United States, also check the destination’s rules for carrying medicines; TSA approval does not establish that another country permits a particular drug.
Solid snacks are generally straightforward to pack in a carry-on. Foods that are liquid, gel-like or spreadable may be subject to the liquids limit, even when sold as food. Yogurt, salsa, jam, dip and nut butter are examples worth checking before packing. If you are unsure how a particular food will be classified, look it up in TSA’s item search rather than relying on its packaging or label.
Food may be inspected separately if it makes an image difficult to interpret during screening. Keep it accessible and follow the officer’s instructions if asked to remove it. For international travel, remember that airport screening rules are only one consideration: a country may restrict the entry of certain foods even if they passed U.S. security screening.
Large electronics may need to be removed from your bag at some checkpoints, while other screening lanes may use different procedures. Pack devices so you can take them out without unpacking everything, but wait for the signs or officer’s directions before doing so. A security rule does not guarantee that an item will remain in your possession if it cannot be screened safely.
Power banks and spare lithium batteries belong in carry-on baggage. Protect loose battery terminals from contact with metal objects, and check your airline’s requirements for battery capacity and device transport. Rules can differ for installed batteries, damaged batteries and specialized equipment, so do not assume that guidance for a small phone power bank covers every battery.
Do not pack a knife in your carry-on. For scissors, tools and other sharp or potentially dangerous items, check the exact item in TSA’s lookup tool; the answer can depend on its design. If you plan to put a permitted sharp item in checked baggage, wrap or secure it so it cannot cause injury during handling or inspection.
Firearms require particular care. They cannot go through the checkpoint in carry-on baggage. If you intend to transport one, check TSA’s current firearm guidance and your airline’s instructions before arriving, including requirements for declaration, a locked hard-sided case and ammunition. Laws may also differ at your destination, so TSA’s screening rules are not the only rules to consider.
Bring an identification document accepted by TSA and have it ready with your boarding details. Accepted forms can change, so confirm the current list on TSA’s identification page before travel rather than assuming that a familiar card will qualify. If you arrive without acceptable ID, tell a TSA officer. TSA may be able to verify your identity and conduct additional screening, but this is not guaranteed to let you proceed; allow extra time and contact your airline if the problem could affect your flight.
At the checkpoint, follow posted instructions and directions from officers. You may be asked to place belongings on a conveyor, remove certain items or undergo additional screening. Procedures can vary by lane and airport, so do not rely on what happened at a different checkpoint. TSA PreCheck changes the screening process for eligible travelers, but membership does not remove the need to follow officer instructions or resolve an item-specific concern.
If an officer identifies an item that cannot pass through, ask what options are available before leaving the checkpoint. Depending on the airport, your timing and the item, you may be able to return it to someone outside the screening area or place it in checked baggage if your airline allows it. Do not count on having time or access to do either. The simplest way to avoid a last-minute decision is to check questionable items before leaving home.
The 3.4-ounce container limit is the standard rule for liquids in carry-on baggage, not a general limit for checked luggage. Larger toiletries may be packed in checked baggage when permitted, but hazardous-material rules and airline restrictions still apply.
Empty reusable bottles can generally pass through the checkpoint. Fill one after screening, or bring a drink only if it meets the carry-on liquids rule.
TSA screening guidance does not generally require prescription medicine to be in its original container, but keeping labels and packaging can make it easier to identify what you are carrying. Check destination-country rules separately if you are travelling internationally.
TSA screens bags for security, while the airline controls its baggage allowance and decides how to handle cabin-bag capacity. If an item cannot pass screening in your carry-on, ask what options are available; do not assume the airline can check the bag at that point.
Tell a TSA officer as soon as you reach the checkpoint. TSA may attempt to verify your identity and subject you to additional screening, but permission to continue is not assured, so arrive early and contact your airline if needed.
The most reliable TSA questions and answers are item-specific. Before packing, check TSA’s current guidance for anything unusual, keep medical supplies and batteries accessible, and confirm your airline’s separate baggage rules. At the airport, follow the screening instructions given for your lane rather than assuming the process will match a previous trip.
