Airport security is smoother when you know the rules in advance. While details vary by country, the core principles are widely shared. Here's what to know to pack right and move through quickly.
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The Liquids Rule
The widely used rule limits carry-on liquids to containers of 100ml (3.4 oz) or less, all fitting in a single clear, resealable bag of about one litre. This covers liquids, gels, pastes, and aerosols — including things like toothpaste and sunscreen. Some airports are rolling out new scanners that relax this, but assume the standard rule unless told otherwise.
Electronics
Larger electronics like laptops and tablets usually need to come out of your bag for screening (again, newer scanners are changing this). Keep them accessible near the top of your bag to save time.
What You Can't Bring
- Sharp objects and tools over certain lengths in carry-on.
- Liquids over 100ml in carry-on (pack them in checked bags).
- Flammable items; certain batteries have specific rules.
- Check country-specific restrictions for your departure point.
Speed Through Security
- Have your liquids bag and electronics easily accessible.
- Wear easily removable shoes and minimal metal.
- Empty pockets into your bag before the queue.
- Arrive early enough to avoid rushing.
TSA PreCheck, Global Entry & Fast-Track Lanes
Trusted-traveler programs let you skip the longest lines and keep shoes, belts, and laptops in place. In the US, TSA PreCheck covers domestic security lanes, while Global Entry adds expedited customs on international arrivals (and includes PreCheck). Many other countries run their own fast-track schemes — the UK has Registered Traveller, and the EU is rolling out its Entry/Exit System. If you fly more than a couple of times a year, the time saved usually justifies the modest application fee.
Traveling with Food, Medication & Special Items
Solid foods are generally fine in carry-on, but anything spreadable, pourable, or gel-like (yogurt, peanut butter, soup) counts as a liquid and must follow the 100ml rule. Medications are exempt from the liquids limit — bring them in reasonable quantities and declare them at the checkpoint if they exceed 100ml. Baby formula, breast milk, and juice for infants are also allowed in larger amounts. Powders over 350ml (about 12 oz) may need separate screening on some routes, so keep them accessible.
Frequently Asked Questions
What is the liquids rule for carry-on?
The standard rule limits carry-on liquids to containers of 100ml (3.4 oz) or less, all fitting in one clear, resealable bag of about a litre. This includes gels, pastes, and aerosols like toothpaste and sunscreen. Pack larger liquids in checked bags. Some airports are introducing scanners that relax this.
Do I need to take my laptop out at security?
At most airports, yes — laptops and larger electronics usually must be removed from your bag for separate screening, though newer CT scanners are eliminating this at some airports. Keep electronics near the top of your bag for quick access.
What is the 3-1-1 rule?
The "3-1-1" rule is the US shorthand for the liquids limit: liquids in containers of 3.4 oz (100ml) or less, packed in 1 quart-sized clear resealable bag, 1 bag per passenger. Most countries follow the same 100ml standard even if they don't use the "3-1-1" name.
Do I have to take my shoes off at security?
It depends on the airport and the scanner. In the US, standard lanes often require shoe removal, while TSA PreCheck lets you keep them on. Many airports in Europe and Asia don't require it at all. Wearing slip-on shoes saves time either way.
Can I bring food through airport security?
Solid foods (sandwiches, fruit, snacks, baby food solids) are generally allowed in carry-on. Spreadable or pourable items like yogurt, peanut butter, and soup count as liquids and must follow the 100ml rule. When in doubt, pack it in your checked bag.
Are medications subject to the liquids rule?
No — prescription and essential medications, including liquids over 100ml, are allowed in carry-on. Bring them in reasonable quantities, keep them accessible, and declare them to security if they exceed the standard liquid limit.
Is TSA PreCheck or Global Entry worth it?
If you fly more than a couple of times a year, usually yes. Both let you use faster lanes and keep shoes, belts, and laptops in place. Global Entry includes PreCheck plus expedited customs on international arrivals, making it the better value for international travelers.
About the author
SK Kutubuddin · Founder & Editor
The founder and editor of Travel and Time. An aeronautical engineer with close to two decades in aviation, I build the site’s flight, distance, and trip-planning tools myself and check every figure before it goes live. I write from Kolkata, India.
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