Carry-on rules by airline type: what to check before you fly
Few things cause more surprise fees than cabin baggage. Every airline sets its own rules for size, weight and how many bags you can bring on board — and the rules can change by fare type and route. Rather than list numbers that change often, this guide explains the patterns and exactly what to check on your airline’s official site.
Personal item vs carry-on
Most airlines distinguish between two types of cabin bag:
- Personal item — a small bag such as a backpack, handbag or laptop bag that must fit under the seat in front of you.
- Carry-on (cabin bag) — a larger bag, often a small wheeled suitcase, that goes in the overhead bin.
Whether both are included depends on the airline and fare. Each has maximum dimensions, and some airlines also set a weight limit.
Common patterns by airline type
Full-service airlines traditionally include a personal item and a full-size carry-on in economy. On some routes their basic economy fares remove the full-size carry-on, restrict seat selection, or board you last; rules differ between airlines and between domestic and international flights.
Low-cost and ultra-low-cost airlines often include only a personal item in their cheapest fare. A larger cabin bag is sold as an add-on or as part of a bundle, and it is usually cheaper to add it when booking or online than at the airport or gate.
Airlines in Asia and parts of Europe more often apply a weight limit to cabin bags, sometimes combined for the carry-on and personal item, and may weigh bags at check-in or boarding.
What to check before you book
- Is a full-size carry-on included in this specific fare, or only a personal item?
- What are the maximum dimensions, including wheels and handles?
- Is there a weight limit, and does it apply to each bag or to all cabin bags combined?
- How much does adding a bag cost now versus at the airport?
- If you are on a codeshare or a connecting itinerary with different airlines, whose rules apply? Usually the operating or first marketing carrier’s rules — check your booking.
The airline’s official baggage page is the authoritative source; partner sites like Aviasales and Kiwi.com also show baggage information at booking.
How to avoid gate fees
- Measure and weigh your bags at home — a cheap luggage scale pays for itself quickly.
- Choose a soft bag that can squeeze into sizers.
- Wear your bulkiest layers and shoes on the plane.
- Buy any needed bag allowance online when you book.
- Check in online and keep your boarding pass on your phone where allowed.
Liquids and security
Security rules for liquids are separate from airline baggage rules. Many airports limit liquids in hand luggage to small containers placed in a clear bag, but some airports with newer scanners have relaxed or changed these limits. Rules can differ for your return journey, so check the current guidance from the security authority at each airport you depart from — for example the TSA in the U.S.
Lithium batteries, including power banks and spare camera batteries, generally must travel in the cabin and not in checked bags. Airlines may limit their size and number.
Comparing fares fairly
When comparing a low-cost fare with a full-service fare, add up the bags and seats you need on both. Farerly’s results include a filter to exclude basic economy fares, and our cheap flights guide explains the full baggage math. If you are flying short hops in Europe or Asia, see our London and Bangkok guides for local tips, or check deals from London.
Checked bags: the other half of the picture
Checked baggage rules follow similar patterns. Long-haul international economy fares on full-service airlines often include at least one checked bag, but this depends on the airline, route and fare. Domestic fares and low-cost airlines frequently charge for every checked bag. Weight limits and sizes vary, and overweight or oversized bags can be expensive. Many airlines charge less when you add bags online in advance than at the airport.
On itineraries combining several airlines on one ticket, bags are usually checked through to your final destination. On separately booked tickets, you normally need to collect and re-check your bags, and each airline’s allowance applies separately.
Special items: strollers, instruments and medical devices
- Strollers and car seats: many airlines allow these for children without counting them as standard bags, often checked at the gate. Rules vary.
- Musical instruments: small instruments may fit in the cabin as a carry-on; larger ones may need an extra seat or must be checked. In the U.S., there are federal rules on carrying small instruments, but airlines’ own policies apply in practice.
- Medical devices and medication: mobility aids and many medical devices are usually allowed in addition to normal allowances. Keep essential medicines in your hand luggage with prescriptions where appropriate.
- Duty-free purchases: liquids bought after security may be allowed on board, but on connecting flights they may be screened again. Keep them sealed in the store’s bag with the receipt.
Always confirm with your airline before you fly.
What happens if your bag is too big
If your cabin bag exceeds the airline’s limits, staff may require you to check it, often for a fee that is higher than prepaying online. On full flights, airlines sometimes ask passengers to check cabin bags at the gate free of charge because there is no overhead space; boarding later makes this more likely. Keep medicines, valuables, documents, chargers and batteries in a small personal item so you can hand over the larger bag easily.
A pre-flight bag checklist
- Read your booking confirmation for the exact allowance on each flight.
- Measure your bag, including wheels and handles.
- Weigh it if your airline has cabin weight limits.
- Pack liquids according to the rules at your departure airport.
- Put batteries and power banks in your hand luggage.
- Keep passport, medicines and valuables in your personal item.
- Add any extra bags online before you reach the airport.
Spending two minutes on this list can save a fee and a stressful scramble at the gate. Remember that rules change — the airline’s official baggage page always has the final word.
Rules for connecting flights
If your trip combines a long-haul flight with a short regional one, the smaller aircraft may have less overhead space and stricter limits. Pack to the strictest allowance on your itinerary so you are not caught out halfway through your journey.
Frequently asked questions
Are cabin bag rules the same on all routes?
No. The same airline may apply different rules to domestic, short-haul and long-haul flights, and to different fare types.
Do airlines really measure bags?
Some check rarely; others check at the gate. It is safest to assume your bag may be measured.
Can I bring a power bank?
Generally yes in the cabin, not in checked bags, within size limits set by the airline and regulators.
Planning a low-cost trip? Compare fares from London or Miami with bags included.
Packing light: a quick list
- Pick a colour palette so clothes mix and match.
- Roll clothes or use packing cubes.
- Bring travel-size toiletries or buy at your destination.
- Download maps, tickets and entertainment before you go.
- Use an eSIM instead of carrying extra devices for data.
Compare flights
Compare live prices with our partners Affiliate — links open a one-way search about a month out; change dates on the partner site. Disclosure.
Before you go
Affiliate links: Farerly may earn a commission at no extra cost to you. The partner is the seller.