Packing a carry-on bag means checking the liquid rules for each airport on your trip. Here is what the UK government and the US Transportation Security Administration (TSA) publish.

This guide is based on the public sources listed at the end. We have not tested the products or services mentioned.

This is a short reference page. The full guide is Travel and Gadgets: Power Banks on Planes, Hand Luggage Liquids, USB-C Power and Safe Listening.

United Kingdom (GOV.UK)

  • At most UK airports, liquid containers in hand luggage are capped at 100 ml, even if only part-filled. Some airports allow up to 2 litres.
  • Where asked, use one clear resealable bag per person, about 1 litre (roughly 20 cm by 20 cm), that closes without being tied, and show it at security.
  • At all UK airports, up to 2 litres is allowed for essential medical needs, special diets, and baby food or milk.
  • Airport-bought or duty-free liquids can pass if sealed in a security bag with a visible receipt. Do not open the bag until your final destination.
  • Frozen liquids are not allowed.
  • Check the departure airport, any transit airport and the return journey.

United States (TSA)

  • Liquids, aerosols, gels, creams and pastes in carry-on must be in containers of 3.4 oz (100 ml) or less, in one quart-size bag kept separate from the carry-on. Larger containers go in checked baggage.
  • Medications and infant and child nourishments are exempt.
  • Duty-free liquids over 3.4 oz bought within 48 hours on inbound international trips may be allowed in a sealed tamper-evident bag with the receipt, though TSA recommends checking them.
  • TSA says rules may change with airport technology, so check before you fly.

Cabin bag size

Size limits are set by each airline, so check yours. For luggage listings, compare internal and external dimensions, whether wheels and handles are included, and the empty weight. See our guide to choosing a handbag or backpack online.

Last checked: 15 October 2026. Sources: GOV.UK, hand luggage liquids; TSA, liquids, aerosols and gels rule.