Carry-on rules 2026: size limits, the liquids rule, and what you can bring

There are two ways to learn the carry-on rules. The first is to read a guide like this one, calmly, on the sofa. The second is to learn at the check-in desk that your bag is 3 cm over the airline's sizer, then pay $55 to $110 to check it on the spot — the most expensive price a plane ticket charges for not paying attention.

This piece is so you do the first.

The problem is that "carry-on" has become one of the slipperiest words in aviation. There is no single rule. There's the regulator's baseline. There's each airline's rule, which changes by fare and by cabin. There's the destination country's rule, which changes for security reasons. And there's the specific airport's rule, which in 2026 changed again because of new scanners. We'll walk through all of them, with numbers.

Carry-on dimensions: the number that changes by airline

Regulators typically guarantee passengers the right to bring up to 10 kg (22 lb) of cabin baggage at no extra cost — that's the legal floor in Brazil, set by the aviation authority ANAC, and a common baseline elsewhere. No airline can offer you less than that in the cabin on a domestic flight.

What regulators usually don't fix rigidly is the dimension. They let each carrier set the size, which is exactly why the sizer varies. The most common reference the market has settled on is:

55 x 35 x 25 cm — about 22 x 14 x 10 in (height x width x depth).

Note one detail that trips up a lot of people: those measurements include wheels, handles and external pockets. Your bag's tag might say "55 cm," but if the wheels add another 3 cm, the metal sizer at the gate will fail it. Measure the bag closed, packed full, with everything sticking out — not the number from the ad.

GOL, LATAM, Azul: the real ranges in 2026

Here the numbers diverge, and this is exactly where you save or lose money.

• Azul — the most conservative: 55 x 35 x 25 cm and 10 kg. The pure reference standard.
• LATAM — dimensions of 55 x 35 x 25 cm, but a weight allowance that varies by fare and cabin. Many conditions work off a 12 kg reference instead of 10. In other words: depending on your fare, you get 2 extra kg of slack.
• GOL — works with up to 12 kg on a good share of tickets, and the airline itself warns the number differs by the date the ticket was issued: older tickets had a lower limit. If you bought long ago, check the rule on YOUR ticket, not the one on the site today.

The practical lesson: 12 kg on one airline is 10 kg on another. If you travel right up against the weight limit, a bag that clears one carrier can be stopped at another. Always confirm on the airline's baggage page with your booking code in hand — allowances can change without notice, and this number has a short shelf life.

Personal item vs. carry-on: they're two different things

A lot of people think "personal item" is a synonym for carry-on. It isn't. They're two separate pieces, and you're entitled to both.

• Carry-on: the wheeled bag or larger backpack that goes in the overhead bin. ~55 x 35 x 25 cm, 10 to 12 kg.
• Personal item: the purse, small backpack, laptop bag or toiletry case that fits under the seat in front of you. Reference dimension of up to about 45 x 35 x 20 cm.

In practice, this is where the light-traveler's tactic lives: most of the cheapest fares ("basic," "light," "promo") strip out the overhead carry-on and leave only the personal item. If your ticket is one of those, your whole trip fits under the seat — and a well-organized 45 x 35 x 20 cm backpack easily handles an entire weekend.

International flights: the tighter standard

Flying abroad, the sizer is usually stricter, not roomier. IATA — the global airline association — suggests 55 x 35 x 20 cm (note: 20 cm depth, not 25). Some airlines accept 55 x 40 x 20 cm. The European low-cost carriers (Ryanair, Wizz, easyJet, Vueling) are the most ruthless: the free personal item is tiny (something like 40 x 20 x 25 cm) and a "real" cabin bag is almost always paid separately.

In 2026 IATA revived a proposal for a universal cabin standard — around 22 x 14 x 9 in (~56 x 36 x 23 cm) — to end this Babel of sizers. It's not global law yet. Until it is, the rule is singular: open the baggage page for the exact airline you're flying, not one for "airlines in general."

The liquids rule: 100ml, 1 litre, and the 2026 earthquake

The rule everyone knows by heart: on an international flight, liquids, gels and aerosols only clear carry-on security in containers of 100ml (3.4 oz) or less each, all together inside a single clear, resealable plastic bag of up to 1 litre (the zip-top, roughly 20 x 20 cm). One bag per passenger. It's the ICAO rule, mirrored by the US "3-1-1" (3.4 oz = 100ml).

Three things nobody tells you that get flagged at the scanner:

1. What counts is the container's capacity, not its contents. A half-empty 150ml tube gets stopped — even with only 70 ml inside. The officer reads the label, not the liquid.
2. "Liquid" is broader than it sounds. Toothpaste, sunscreen, roll-on deodorant, yogurt, honey, jam, perfume, liquid foundation, even soft cheese all count. When in doubt: if it squeezes or spreads, it's a liquid.
3. Many domestic flights don't enforce it. The 100ml restriction is aimed at international travel. On a purely domestic hop in some markets you can carry a 400ml shampoo bottle in your backpack with no problem. Plenty of people throw them out for nothing. (Confirm at the airport, but that's the prevailing rule.)

The earthquake: European airports are scrapping the 100ml limit

Here's the biggest change of 2026, and the one that confuses people most. Europe has been installing CT scanners (C3) that see inside a bag in 3D. Where those scanners are live, the 100ml limit has fallen — you can carry liquids in containers of up to 2 litres, and you don't even have to pull electronics and liquids out of your bag on the belt.

Where it already applies (early 2026):

• London Heathrow — scrapped the limit across all four terminals on 23 January 2026.
• Other UK airports that finished the scanner swap: Gatwick, Birmingham, Bristol, Edinburgh and Belfast.
• On the continent, a scattered set of hubs: Rome Fiumicino, Milan Linate, Bologna, Dublin and Prague (Terminal 2), plus regional airports in Poland, Lithuania, Romania, Denmark and Malta.

The danger is in the patchwork. Rollout is uneven. Frankfurt and Munich, for example, have only converted some lanes — on the same trip you can face different rules outbound and inbound. A 100ml bag packed the old way clears anywhere; a 500ml water bottle you bought before boarding at Heathrow can be stopped at your next connection if that airport still runs an old scanner.

The survival rule: pack for the most restrictive airport on your route, not the most modern one. Until the rollout is finished (and there's no single reliable date), keep treating 100ml as the standard and treat the 2-litre allowance as a bonus at that specific departure airport. Confirm on the airport's official site the week you travel.

What you can and can't bring in your carry-on

Here's a logic flip that confuses almost every first-time flyer: the most valuable and most dangerous things go in your HAND, not the hold. Batteries, medication and electronics stay with you. Knives, scissors and big liquids go below.

Electronics and batteries: always in the cabin

• Laptop, tablet, camera, phone, headphones: carry-on, always. Not because of a rule — because of common sense. Checked baggage gets lost, rummaged and thrown. Never put anything expensive in the hold.
• Loose / spare lithium batteries (rechargeable cells, camera batteries, spares): banned from checked bags. They have to travel in the cabin, with you. A lithium battery in the hold is a fire risk no one can put out mid-flight — which is why the rule is hard.

Power banks: the new 2026 rules

This is the item that changed the most, and where the most people will get caught off guard in 2026. Aviation authorities — Brazil's ANAC among the strictest — have rewritten the rules for portable chargers. What now applies:

• Always in your carry-on. Power banks in the hold are banned — no exceptions.
• Limit by capacity (in Wh, not mAh):
  • Up to 100 Wh: allowed, no approval needed. Covers the vast majority of pocket power banks.
  • Between 100 and 160 Wh: only with prior airline approval.
  • Over 160 Wh: banned. It stays at the airport.
• Maximum of 2 power banks per passenger.
• Charging the power bank onboard is banned, and regulators advise against using it in flight to charge a phone or tablet.
• Protected terminals against short circuits — in the original packaging or with the contacts taped over.

How do you find your Wh? The math: Wh = (mAh ÷ 1000) x Voltage. A common 20,000 mAh power bank at 3.7 V gives ~74 Wh — comfortably under the limit. Most travel models sit below 100 Wh. If yours is huge (26,800 mAh+) or a power-station type, check the label. And remember: any airline can be stricter than the regulator — confirm before you fly.

Medication: allowed, but bring the prescription

• Personal medication goes in your carry-on — you don't want your insulin, your blood thinner or your heart meds lost in a mishandled bag.
• Liquid medication (syrup, insulin, eye drops, saline) is an exception to the 100ml rule: it can exceed 100ml if it's a medical necessity. Bring a prescription or doctor's note (ideally in English on an international flight) and declare it at the scanner. Without the document, the officer can stop it.
• Syringes and needles accompanying the medication: allowed with the prescription.

Food: more allowed than you'd think

• Solid food (sandwich, cookies, fruit, chocolate, nuts, firm cheese) clears carry-on security fine, domestic or international.
• Pasty or liquid food (yogurt, a jar of honey, jam, peanut butter) falls under the 100ml rule on international flights. Baby food and breast milk are exceptions — allowed in reasonable quantities.
• Watch destination customs, which is a separate story: many countries (US, Australia, much of Europe) ban the entry of meat, dairy, fruit and seeds, even if the airline lets you board with them. Carrying the cheese is one rule; bringing it into the country is another.

What you CAN'T carry on (goes to the hold or stays home)

• Sharp or pointed objects: long-blade scissors, pocket knife, knife, loose razor blade, large pliers, big screwdriver. These go in the hold. (Nail scissors and disposable razors usually clear, but it's the officer's call.)
• Liquids over 100ml on an international flight: hold.
• Flammables, explosives, gases: torch lighter, camping gas, fireworks, large spray paint. Generally banned on both sides — check the airline's dangerous-goods list.
• Selfie stick and large tripod: vary by airline — many require you to check them.

Carry-on vs. checked: when each one pays off

The difference isn't just size. It's a travel philosophy.

Checked baggage costs time (the check-in queue, the wait at the carousel on arrival) and money (on a domestic flight, checking 23 kg can be free on the right fare or run from $18 to over $100 if bought last-minute at the desk — the allowance varies by fare ever since Brazil's ANAC Resolution 400 let airlines sell tickets with no bag included). The standard checked weight is 23 kg (50 lb) per piece, domestic and international, on most airlines.

Carry-on costs discipline. You get ~10 to 12 kg and a small space to fit everything. In exchange: zero check-in queue, zero carousel wait, zero risk of a lost bag, and the freedom to step off the plane and walk out.

The pocket rule: buy the checked-bag allowance together with your ticket, never at the airport. The price gap between buying ahead and buying at the desk is the biggest legalized heist in aviation — it can triple.

Tactics for traveling carry-on only

Traveling with just a carry-on isn't about bringing little. It's about bringing right. The tactics that actually work:

• The 3-shoes rule, max: one on your feet, two in the bag. Shoes are the item that steals the most space and weight.
• Roll, don't fold. Rolled clothes take less room and wrinkle less. Packing cubes transform a bag's capacity.
• Wear the heaviest item on the flight: coat, jacket, boots. What you wear doesn't count toward bag weight. No airline weighs the passenger.
• A permanent liquids kit: a 1-litre bag assembled once, with reusable 100ml bottles, ready forever. Buy small toothpaste, shampoo and sunscreen, or decant into the bottles.
• Mind the personal item: it's your safety net. Laptop, charger, power bank, medication, an emergency change of clothes and documents go in it. If the airline forces you to gate-check the cabin bag (it happens on a full flight), the personal item stays with you — and everything that matters is in it.
• Weigh it at home. A hanging luggage scale costs about $8 and pays for itself the first time you don't have to repack on the airport floor.

Carry-on-only isn't for every trip. A month in Patagonia with hiking gear? Check it. A weekend in Buenos Aires or five days in Lisbon? It fits in your hand, and you save two hours of airport across the whole trip.