The carry-on liquid limit is one of the simplest airport rules to follow once you know the numbers, and one of the easiest to get caught out by if you do not. Bring a full-size shampoo in your hand luggage and it goes in the bin at security, along with the time you spent queuing.
This guide covers exactly how much liquid you can take in a carry-on, what the 3-1-1 rule means, what airport security counts as a “liquid,” the exceptions for medicine and baby supplies, and how the rule works on international flights.
Table of Content
- Quick answer
- The 3-1-1 rule explained
- What counts as a liquid
- Liquids on international flights
- Exceptions: medicine, baby supplies, duty-free
- New airport scanners and the 100 ml rule
- How to pack liquids for carry-on
- What about checked baggage?
- FAQs
Quick answer
In carry-on baggage, each liquid container can hold up to 3.4 ounces (100 ml), and all your containers must fit inside one quart-sized (about 1 litre) clear, resealable bag — one bag per passenger. Anything larger than 100 ml goes in checked baggage, with a few exceptions for medicine and baby supplies. The same limit applies on international flights.
The 3-1-1 rule explained
In the United States, the TSA sums up the carry-on liquid rule as 3-1-1:
- 3.4 — each container is 3.4 ounces (100 ml) or smaller
- 1 — they all fit in one quart-sized clear, resealable bag
- 1 — one bag per passenger
The detail that trips people up is that security looks at the container size printed on the bottle, not how much is left inside. A half-empty 150 ml moisturiser is still refused, because the bottle is bigger than 100 ml. Decant into travel-sized bottles instead, or pack the full-size one in your checked bag.
What counts as a liquid
Airport security treats anything you can pour, squeeze or spread as a liquid. That is broader than most travellers expect and includes:
- Water, juice, and other drinks
- Toiletries: shampoo, conditioner, shower gel, liquid soap
- Toothpaste, creams, lotions and gels
- Aerosols and sprays, including deodorant sprays and dry shampoo
- Make-up with a liquid or gel texture: mascara, foundation, lip gloss
- Spreadable and pourable foods: peanut butter, jam, honey, yoghurt, soft cheese, soups and sauces
Solid versions usually escape the rule entirely. A solid stick deodorant, a bar of soap, solid perfume, lipstick, and solid snacks are not treated as liquids, which makes them a smart way to save space in your quart bag. Powders are allowed, though in the US quantities over 12 ounces (350 g) may get extra screening.
Liquids on international flights
The 100 ml container limit is an international security standard, not just a US rule, so it applies almost everywhere. In the UK and Europe you will see the same restriction described as the LAGs rule (liquids, aerosols and gels): containers up to 100 ml, inside one transparent resealable bag of around 1 litre, roughly 20 x 20 cm.
The practical takeaway is that you can pack the same way for a flight out of Dubai, London, Singapore or New York, and your airline does not change it — every airline uses the same 100 ml limit. If you are connecting between countries, plan for the strictest checkpoint on your route, because you may be re-screened at a transfer airport.
Exceptions: medicine, baby supplies, duty-free
Medication. Essential liquid medicines are allowed in quantities over 100 ml. Take them out at security, tell the officer, and expect them to be screened separately. Carrying a prescription or a doctor’s note makes this smoother, especially on international trips.
Baby supplies. Formula, breast milk, and baby food are permitted in reasonable quantities above 100 ml when you are travelling with an infant. Declare them at the checkpoint for separate screening.
Duty-free. Liquids bought after security can exceed 100 ml. If you have a connecting flight, keep them sealed in the tamper-evident bag with the receipt inside, or they may be taken at your transfer airport.
New airport scanners and the 100 ml rule
You may have read that the 100 ml limit is being scrapped. Some airports have installed newer CT (computed tomography) scanners that can, in theory, allow larger liquids and let you leave them in your bag. In practice the rollout has been uneven: several UK airports that relaxed the limit were told to reinstate 100 ml, and the rule still varies by airport and equipment.
Until the standard changes everywhere, the safe assumption is that the 100 ml limit still applies. Pack to that limit and check your specific departure airport’s website if you are hoping to carry more.
How to pack liquids for carry-on
- Decant toiletries into 100 ml travel bottles, or buy travel-sized versions.
- Swap liquids for solids where you can: bar shampoo, stick deodorant, solid perfume.
- Keep the clear bag at the top of your carry-on so it is quick to pull out at security.
- Bring an empty water bottle and fill it after the checkpoint.
- Put anything over 100 ml in your checked bag before you leave home.
Not sure what else to pack? Our free packing list generator builds a checklist based on your trip length and style, liquids included.
What about checked baggage?
The 100 ml limit does not apply to checked baggage, so full-size toiletries belong there. There are still limits on things like alcohol and aerosols in checked baggage, and it is worth knowing them before you pack. If a checked bag pushes you over your airline’s weight allowance, check the cost first with our baggage fee calculator.
Frequently asked questions
How many ounces of liquid can you bring on a plane?
Each container can hold up to 3.4 ounces (100 ml), and every container must fit inside one quart-sized (about 1 litre) clear, resealable bag. It is the size of the container that matters at security, not how much liquid is left inside it.
What is the 3-1-1 rule?
It is the shorthand for the TSA carry-on liquid rule: 3.4 ounces (100 ml) per container, 1 quart-sized clear bag to hold them, and 1 bag per passenger.
Do liquids have to be in a clear bag?
Yes. For carry-on, all your travel-sized liquids must fit in a single transparent, resealable bag of about 1 litre (roughly 20 x 20 cm) so security can screen them quickly.
Can I bring a container larger than 100 ml if it is only half full?
No. Security judges the container’s labelled size, not the amount inside. A 200 ml bottle is not allowed in carry-on even if it holds only a little liquid. Pack larger containers in checked baggage instead.
Does the 100 ml liquid limit apply to international flights?
Yes. The 100 ml container limit and the single clear bag are an international security standard, so the same rule applies on flights from the UK, Europe, the Gulf, Asia and most other regions.
Can I take an empty water bottle through airport security?
Yes. An empty reusable bottle is allowed through security. Fill it at a water fountain or cafe after the checkpoint so you are not paying for water airside.
What items count as a liquid?
Anything pourable or spreadable: water and drinks, toiletries, toothpaste, creams, lotions, gels, aerosols, mascara and lip gloss, plus foods like peanut butter, jam, yoghurt, honey, soups and sauces.