On most flights, liquid containers in carry-on bags must be 3.4 ounces (100 milliliters) or smaller and fit in a one-quart clear bag.
If you have ever stood at airport security wondering how big can liquid be on an airplane, you are in good company. Rules about bottles, tubes, sprays, and drinks feel confusing, and the rules are not identical in every country. The good news is that once you understand a few simple patterns, you can pack toiletries and drinks with a lot less stress.
This guide walks through the standard 100 milliliter rule, newer airports that allow bigger bottles, what happens with checked bags, and how special items like medicine or baby milk fit in. By the end, you will know exactly how to plan your liquids for your next trip without last-minute binning at the scanner.
Carry-On Liquid Size Rules At A Glance
Most travelers still pass through checkpoints that follow the familiar “3-1-1” style rule. In simple terms, each liquid container in your carry-on must be 3.4 ounces (100 milliliters) or less, and all of them together must fit inside a single, clear, resealable bag with a capacity of around one quart or one liter. That bag then goes through security with your hand luggage. :contentReference[oaicite:0]{index=0}
This rule covers liquids, gels, pastes, creams, foams, aerosols, and many liquid foods. It is based on container size, not how much is left inside. A half-empty 200 milliliter shampoo bottle still counts as 200 milliliters. Many airports in North America and parts of Asia and Europe follow this pattern, although staff may describe it with slightly different words.
The 3-1-1 Style Rule In Simple Terms
- Each container in your carry-on: up to 3.4 oz / 100 ml.
- All small containers together: must fit in one clear, resealable one-quart or one-liter bag.
- One liquids bag per person in most cases.
This structure gives security staff a predictable way to screen many passengers quickly. It also helps you plan your liquids in advance instead of re-packing everything in the queue.
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Common Liquids And Typical Size Limits
| Liquid Type | Carry-On Limit (Typical) | Checked Bag Notes |
|---|---|---|
| Water, Soft Drinks, Juice | Up to 100 ml per container; larger bottles bought after security are fine on board | Large bottles usually allowed; pack well to prevent leaks |
| Shampoo, Conditioner, Body Wash | Travel bottles up to 100 ml each | Full-size bottles allowed; wrap in plastic or a toiletry bag |
| Toothpaste, Face Cream, Lotions | Tubes and jars up to 100 ml | No strict size limit in most cases; watch weight limits |
| Liquid Makeup, Mascara, Lip Gloss | Each piece treated as a small liquid, up to 100 ml | Allowed; pack to avoid breakage or smears |
| Alcoholic Drinks From Duty-Free | Large bottles allowed only if sealed in a special security bag with receipt | Allowed up to the airline’s alcohol and customs limits |
| Aerosol Deodorant, Hairspray | Up to 100 ml per can; some airports also cap total aerosol volume | Larger cans often allowed; check airline rules for total aerosol quantity |
| Liquid Food (Soups, Sauces, Yogurt) | Up to 100 ml per container; large tubs are not allowed | Often allowed but risky for leaks; double-bag containers |
| Medically Necessary Liquids | Often allowed in larger volumes after extra screening | Usually allowed; carry proofs such as prescriptions or letters if possible |
| Baby Milk, Formula, Baby Food | Can exceed 100 ml; security may screen each container separately | Allowed; helpful to keep everything together in one pouch |
Always remember that staff at the checkpoint have the final say. Any item that cannot be screened properly can be refused, even if the label size meets the rule on paper. That is rare, but worth keeping in mind when packing items that are cloudy, very dense, or packed in unusual containers.
How Big Can Liquid Be On An Airplane?
The direct answer is that for carry-on bags, the usual limit is 3.4 ounces or 100 milliliters per container, placed together in a one-quart or one-liter clear bag. That is still the rule for flights that follow the
TSA liquids, aerosols and gels rule
in the United States and similar standards in Canada and many other regions. :contentReference[oaicite:1]{index=1}
The answer changes once you step into airports that have rolled out new CT scanners at security. Some major hubs now allow liquids in containers up to two liters in carry-on bags, with no need to place them in a separate plastic bag, because the scanners can create detailed 3D images of your luggage. Heathrow and several other large airports in the United Kingdom and European Union fall into this group, and more airports are joining over time. :contentReference[oaicite:2]{index=2}
Because rules now differ from airport to airport, the best way to handle how big can liquid be on an airplane is to treat 100 milliliters as your safe default for carry-on bottles. Then, if your departure and return airports both publish a higher limit thanks to new scanners, you can relax the rule for that specific route.
Why Container Size, Not Content, Matters
Security teams work with the printed capacity of the bottle or tube, not the amount inside. That means a 150 milliliter tube that holds only 30 milliliters of cream is still too large for a strict 100 milliliter rule. Staff do not have time to measure the remaining liquid for each passenger, so they rely on the maximum volume printed on the container instead. :contentReference[oaicite:3]{index=3}
This detail explains why travel-size kits sold in many shops label each bottle clearly. When in doubt, always check the number printed on the back or bottom, not the amount you think you have left.
How Big Can Liquid Bottles Be On An Airplane Carry-On Bag
Once you line up with a carry-on bag, staff mostly care about three things: the printed size of the bottle, whether the item counts as a liquid, and how your liquids are packed. If your airport still uses the 100 milliliter rule, any bottle above that size belongs in checked luggage or must be emptied before security. That includes refillable water flasks, large hair products, and big tubes of sunscreen.
At airports that allow containers up to two liters, you can keep larger bottles of water or shampoo in your hand luggage, but only when you depart from that airport and pass through its security lane. On a return leg from a different city that still follows the 100 milliliter limit, those same large bottles may no longer be allowed. This gap often catches travelers by surprise when they buy big products abroad and then fly home.
The safest move is to pack a set of refillable travel bottles that are clearly marked at or below 100 milliliters. That way, even if rules are more relaxed at your departure airport, your liquids still meet the strictest rules you are likely to see on the same trip.
Liquid Size Rules By Region And Airline
Rules on how big liquid can be on an airplane grew from common security concerns, so regional standards overlap a lot. The United States, Canada, and many Asian countries use very similar limits: 100 milliliters per container in a one-liter bag. The European Union set out matching rules for carry-on liquids, though more airports there now host scanner setups that allow larger bottles in hand luggage when local regulators approve them. :contentReference[oaicite:4]{index=4}
Airlines rarely set their own lower carry-on liquid volume limits. Instead, they enforce the rules of the airport and country where you pass through security. Where airlines do step in is with liquids that raise safety issues on board, such as strong alcohol and certain chemicals. Those limits often come from aviation safety rules rather than security screening rules and can apply even to bottles that pass through security without any problem. :contentReference[oaicite:5]{index=5}
Local airport websites remain the best source for last-minute checks. Many publish a short page that sets out current liquid limits and whether CT scanners are in use at that location. It takes only a minute to read those pages and can save you from losing expensive products at the checkpoint.
Why Some Airports Now Allow Bigger Bottles
CT scanners can build a detailed 3D image of your carry-on bag, layer by layer. That level of detail allows staff to rotate and inspect suspicious shapes digitally without asking you to unpack everything. As trial programs showed that these scanners handle liquids in large containers safely, regulators in some regions approved bigger limits for hand luggage where this equipment is in place. :contentReference[oaicite:6]{index=6}
The catch is that rollout is uneven. You might fly out of a large hub with relaxed rules, then connect through a smaller airport that still enforces strict 100 milliliter limits for the next security check. Your liquids must meet the rules of each checkpoint on your route, not only the first one.
Checked Luggage Liquid Limits And Safety
Carry-on rules often feel strict, so travelers sometimes push everything liquid into checked bags. For regular toiletries, drinks, and liquid foods, checked luggage usually has much more relaxed size limits. Aviation regulators and airlines focus more on total weight and on restricting flammable or dangerous liquids than on the size of each everyday container.
That said, alcohol and aerosol products can face extra limits. Many carriers cap the total amount of strong alcohol in checked bags and restrict the size and number of aerosol cans. These rules come from fire safety regulations, so they apply even though the bottles never pass through a passenger security lane. It is always wise to read your airline’s baggage rules before packing large bottles of spirits, fuel, or chemical cleaners.
From a practical angle, checked bags also bounce through conveyor belts and rough handling. Even when a big liquid bottle is allowed, you still need to double-bag it and put it in the middle of soft clothes to reduce spill risks.
Special Liquid Exceptions For Medicines And Baby Items
Many authorities make room for items that travelers genuinely need during a flight. Medically necessary liquids such as certain syrups, saline, or liquid nutrition can often exceed 100 milliliters in carry-on bags. Staff may ask you to separate these items from your other liquids and show prescriptions or letters that explain why you need them while flying. In some cases they also swab or scan the containers separately. :contentReference[oaicite:7]{index=7}
Parents can bring larger amounts of baby milk, formula, and baby food through security. Again, staff may ask to see each container and may run extra screening. One handy habit is to keep all baby liquids in a single pouch, ready to place in a tray by themselves. That makes screening smoother and reduces handling by staff.
The same idea applies to liquid dietary items that a passenger must consume during the flight, such as certain meal replacements. Many countries treat them like medical liquids and give staff the discretion to allow reasonable quantities on a case-by-case basis, even above standard limits.
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Quick Reference For Liquid Size By Scenario
Once you know the main patterns, it helps to match them to common travel situations. The table below gives a quick sense of what you can plan for in different cases.
| Scenario | Carry-On Liquid Size | Simple Packing Tip |
|---|---|---|
| Direct flight from a standard 100 ml airport | Up to 100 ml per container in a one-quart or one-liter bag | Use labeled travel bottles and keep the liquids bag at the top of your carry-on |
| Trip through an airport with new CT scanners | Local rules may allow containers up to two liters | Even if larger bottles are allowed, pack under 100 ml if you will pass other checkpoints |
| Return flight from a country with strict rules | Often 100 ml per container, even if the first airport allowed more | Avoid buying large liquid products airside unless you can keep them sealed for transit |
| Trip with only hand luggage | All liquids must fit in the small liquids bag unless local rules are more generous | Switch bulky items such as shampoo to solid bars where possible |
| Vacation with checked bags | Carry only what you need during the flight in your liquids bag | Put full-size bottles in checked luggage inside sealed plastic bags |
| Travel with medicine or special dietary drinks | Larger volumes may be allowed after extra screening | Carry prescriptions and pack liquids where they are easy to present at security |
| Flying with a baby or toddler | Baby milk and food can exceed 100 ml in many regions | Store all baby liquids together and tell staff about them early in the screening process |
Practical Tips To Pack Liquids Without Stress
Start with your route. Before you pack, check the websites for every airport on your trip and read the section on security liquids. Look for any mention of new scanners and higher container limits, and notice whether staff still ask for a separate liquids bag. Matching your bottles to the strictest airport on that route will keep you safe from surprises.
Next, sort liquids into three groups: items you need during the flight, items you will only need at your destination, and items that are nice to have but not required. Pack the first group into your carry-on within the allowed limits for how big can liquid be on an airplane on that route. Put the second group in your checked bag, secured against leaks. Leave the third group at home or plan to buy those items on arrival.
Finally, think about backups. Solid toiletries such as bar shampoo, solid perfume sticks, and stick deodorant usually do not count toward your liquid allowance and can free a lot of space in your liquids bag. Buying drinks after security instead of bringing them from home also removes one more headache. With a bit of planning, liquid rules stop feeling like a puzzle and turn into a simple packing habit you barely notice.