Carry-On Liquid Bag Planner – 100 ml Rule and One-Bag Check

Cabin liquid rules cause more airport stress than almost any other packing rule, because they are strict and there is no room to argue at the security tray. Every liquid, gel and cream you carry in hand luggage must sit in a container of 100 millilitres or less, and all containers must fit in one resealable transparent bag of about one litre. This planner checks your containers against both limits before you leave home.

The 100 millilitre rule applies to the container size, not to how much is left inside it. A half empty 200 millilitre bottle still breaks the rule, even though it holds only 80 millilitres of product. Security staff judge the size printed on the bottle, so decant products into small travel bottles instead of carrying large bottles that are nearly empty. This single detail catches many travellers.

The one litre bag limit is just as strict. A standard quart bag or a 20 by 20 centimetre resealable bag is the usual size, and everything must fit inside it with the bag able to close. If the bag bulges open, it does not count as closed. Pack the bag at home, close it, and check that it lies flat. Trying to repack liquids at the security line wastes time and often means throwing things away.

A worked example shows how the check works. Eight containers with the largest at 100 millilitres and a total of 700 millilitres pass both rules and need one bag. Change the largest container to 150 millilitres and the same set fails, even though the total is smaller. Raise the total to 1200 millilitres and you need a second bag, which means a second traveller or a checked bag for the extra liquids.

Many everyday items count as liquids under these rules, and travellers forget them. Lip balm, mascara, toothpaste, sunscreen, hand cream, hair gel and even peanut butter all count. Solid soap, solid shampoo bars, powder deodorant and dry makeup do not count, which is why solid toiletries are a smart swap for cabin only trips. Check each item against the liquid definition, not against whether it looks wet.

Medicines and baby food have special allowances in many countries, but they still need care. Essential medicines over 100 millilitres are often allowed with proof, such as a prescription or a doctor letter, and baby milk and food for the journey are usually allowed in reasonable amounts. Rules vary by country and airport, so check the airport website before you fly and keep medicines in their original packaging.

Buying liquids after security is the simplest way to dodge the whole problem. Water, sunscreen and large toiletries bought in the departures shops can usually be carried on board, because they were bought past the checkpoint. This works well for sunscreen and drinks, but do not rely on it for prescription creams or a favourite product that the airport shop may not stock.

Packing liquids well also protects the rest of your bag. Put each bottle in the bag with caps tight, and place the sealed bag near the top of your case so you can pull it out fast at security. A leaked shampoo bottle can ruin clothes and electronics, so wrap the bag in a small cloth or place it inside a second pouch for the flight. A little care here saves a lot of cleaning later.

Different airports enforce the same rules with different strictness, and connecting flights can add a second check. A bag that passed in one airport may be rechecked at a transfer, especially on international routes. Keep the liquid bag accessible for the whole journey, not buried under clothes after the first flight. If you buy duty free liquids, keep the sealed bag and receipt until you reach your final destination.

Keep the liquid bag in an outer pocket of your cabin bag, not buried at the bottom, because you must take it out at every security check. A bag that is easy to reach saves time for you and for everyone behind you in the queue. After security, put the bag back in the same pocket so you can find it again at a connecting flight without unpacking the whole case.

Planificador de Bolsa de Líquidos de Cabina: Regla de 100 ml y Una Bolsa