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what size liquid can you take on an airplane

You can usually take only small containers of liquids in your carry-on, and there are strict limits on size and how you pack them.

Quick Scoop: Standard Rule (TSA & Most Countries)

For most flights (especially from or within the US, and many other countries), the “3-1-1 liquids rule” applies for carry-on bags:

  • Each liquid container: Maximum 3.4 ounces (100 milliliters).
  • Total liquids: All containers must fit comfortably in one clear, resealable quart-size (about 1 liter) bag.
  • Bag limit: One quart-size bag per person in your carry-on.
  • The bottle size matters, not how full it is (a 4 oz bottle is not allowed even if half full in many airports).

This covers:

  • Liquids (water, drinks, shampoo).
  • Gels and creams (toothpaste, lotion, hair gel).
  • Aerosols (hair spray, deodorant).
  • Pastes and similar items.

Checked luggage is different: you can usually pack larger liquid containers there, as long as they follow airline and destination rules (for example, no flammable items).

Important Exceptions

These are often allowed in larger quantities in your carry-on , but you must usually declare them at security and sometimes take them out for separate screening:

  • Medically necessary liquids (prescription medicines, some medical solutions).
  • Baby formula, breast milk, and baby food when traveling with an infant.
  • Duty-free liquids bought after security, in sealed, tamper-evident bags (keep the receipt and don’t open the bag before your final destination).

Rules and how strictly they’re enforced can vary by country, airport, and even individual officer.

Newer Changes in Some Places (Especially the UK & Europe)

While the 100 ml rule still applies in most of the world, some airports are starting to relax it because of new 3D/CT scanners:

  • A few major UK airports (like Heathrow, Edinburgh, Birmingham and others) have begun allowing passengers to carry liquids in containers up to 2 liters in hand luggage through security when using the new scanners.
  • At other UK airports, and at many airports worldwide, the 100 ml / 3.4 oz rule still applies , even if you don’t have to remove liquids from your bag.

This means:

  • On one trip, you might be allowed a 2-liter bottle through security at a modernized UK airport.
  • On another, you might still be limited to 100 ml containers in a quart bag.

Because this is changing over time and isn’t consistent everywhere, always check:

  • Your departure airport’s security rules.
  • Any connecting airports’ rules (you might be re-screened).
  • For US flights specifically, the classic 3-1-1 rule is still the safe assumption.

Simple Rule of Thumb for Your Trip

  1. If you’re unsure:
    • Pack carry-on liquids in containers of 3.4 oz (100 ml) or less , all in a single quart-size clear bag.
  2. If flying from a UK or European airport with “new rules”:
    • Check that airport’s website; some now allow up to 2 liters , but this may not apply at your connecting airport.
  3. For big bottles (shampoo, full-size lotion, large drinks):
    • Put them in checked baggage , or buy drinks after security.

TL;DR:
On most flights, you can only take liquids in containers up to 3.4 oz / 100 ml , all fitting into one quart-size clear bag in your carry-on. Some newer UK/European airport scanners now allow bigger containers (up to around 2 liters), but since rules are not yet universal, sticking to the 100 ml rule is the safest bet unless you’ve confirmed your specific airport’s current policy.