You can usually take only small amounts of liquid in your carry-on , but the exact limit now depends on where you’re flying from and which airport you use.

The classic rule: 100 ml / 3.4 oz

For most of the world, the familiar cabin rule still applies:

  • Each liquid container: max 100 ml (3.4 oz).
  • All your liquids must fit in one clear, resealable bag of about 1 quart / 1 liter.
  • Only one bag per passenger in your carry-on.
  • This covers liquids, gels, creams, pastes, aerosols (e.g., shampoo, toothpaste, lotion, hair gel, perfume, shaving foam).

In practice, this means you can carry several small bottles, as long as:

  • None is bigger than 100 ml.
  • They all fit comfortably in that one small transparent bag.

Checked luggage is different: most liquids are allowed in much larger quantities in checked bags, with separate rules only for things like alcohol.

New scanners and the 2‑liter updates

From 2025–2026 onward, some airports are rolling out new CT security scanners , which are starting to relax the 100 ml rule.

  • At many major UK airports (like Heathrow, Gatwick, Edinburgh, Birmingham), passengers can now take containers up to about 2 liters each in their hand luggage.
  • You usually don’t need to take liquids out of your bag at these upgraded checkpoints.
  • However, not all airports in the UK and Europe are upgraded yet, so some still enforce the 100 ml limit.
  • Similar scanner-based relaxations are starting to appear in the US and elsewhere , but they are not universal and may vary by airport and terminal.

The key catch: what you can bring outbound might differ from what’s allowed at your return or connecting airport, so big bottles can still be taken away mid-journey.

Special items: meds, baby stuff, duty‑free

Some liquids have more flexible rules, even where 100 ml still applies.

  • Medication (liquid)
    • Often allowed in larger quantities than 100 ml if needed during the flight.
    • You may be asked to show documentation or separate them at security.
  • Baby food, baby formula, breast milk
    • Typically allowed in quantities over 100 ml , as “reasonable for the journey”.
    • You may need to present them separately for inspection.
  • Duty‑free liquids
    • Large bottles bought after security are usually allowed if kept in the sealed, tamper‑evident bag with the receipt.
    • On connecting flights, rules can get tricky; some airports may re-screen and potentially confiscate items if they don’t follow their local rules.
  • Alcohol in checked bags
    • Under about 24% ABV (beer/wine): typically no quantity limit beyond airline weight rules.
    • 24–70% ABV (spirits): usually up to 5 liters per person in checked luggage, sealed in original packaging.
    • Over 70% ABV : generally prohibited in both checked and carry-on.

Quick reference table (carry-on)

[9][10][7] [10][1] [8][9][7] [3][10] [7]
Scenario Typical carry-on liquid limit
Most airports worldwide (standard security) 100 ml (3.4 oz) per container, all in one ~1 L transparent bag
Some upgraded UK / other airports with CT scanners Containers up to around 2 L allowed in hand luggage; no plastic bag needed
Liquid medicines, baby food, breast milk Can exceed 100 ml if “reasonable for the journey”; subject to extra screening
Duty-free liquids bought after security Large bottles allowed in tamper-evident bags; may face extra checks on connections
Checked luggage (non-dangerous liquids) Generally much larger amounts allowed; watch airline weight rules

Why this is a “trending” topic now

Liquid rules are back in the spotlight because:

  • New CT scanners are slowly ending the old 100 ml rule at some big hubs.
  • The change is patchy : some airports allow 2 L bottles, others still insist on tiny 100 ml containers.
  • Travelers are sharing mixed experiences on forums:

“Flew out of a new‑scanner airport with a 1L water bottle no problem, but they took it on my connection back.”

  • 2026 is shaping up as a transition year , so many guides now stress: “check your specific airports” before packing.

How to stay safe and avoid losing your liquids

Because rules differ by country, airport, and even terminal, use these simple checks:

  1. Check both airports
    • Look up liquid rules for your departure , destination , and any connecting airports on their official websites.
  2. Assume 100 ml if unsure
    • If you’re not certain an airport uses the new scanners, pack as if the 100 ml / 1-quart-bag rule still applies.
  3. Separate special items
    • Keep medications, baby items, and important liquids easily accessible to show at security.
  4. Use checked luggage for big bottles
    • Put shampoo, full-size lotions, and large drinks in checked bags if you must bring them.

One-sentence TL;DR

If you’re unsure how much liquid you can take on a flight, plan on the safe standard of 100 ml per container, all fitting in one small clear bag , and only relax that rule if your specific airports clearly say they allow larger amounts like up to 2 liters with new scanners.

Information gathered from public forums or data available on the internet and portrayed here.