Baggage Rules, Explained Without the Fine Print

Baggage rules feel inconsistent because they are. Allowances are set by each airline, adjusted by fare type, occasionally overridden by alliance agreements, and enforced with varying enthusiasm depending on how full the flight is.

Here is the structure underneath all of that.

The three categories

Airlines generally split baggage into three buckets.

A personal item is the small bag that fits under the seat in front of you. A handbag, a laptop bag, a small backpack. On the strictest low-cost fares this is the only bag included.

Cabin baggage is the wheeled case or larger backpack that goes in the overhead locker. Typical dimensions sit around 55 x 40 x 20 cm, but every airline publishes its own numbers and some of them are noticeably meaner.

Checked baggage goes in the hold. Weight limits usually land at 20, 23 or 32 kilograms per piece, with 23 being the most common single-bag figure on long-haul tickets.

Why your friend paid nothing and you paid forty

Two differences explain most of it: fare type and route.

Within the same cabin, a basic economy fare often excludes checked baggage entirely, while a standard fare includes one piece. On long-haul routes, checked baggage is more often included by default. Some markets, particularly transatlantic and parts of Asia, use a piece system counting bags. Others use a total weight system where you can distribute weight across bags as you like.

If you booked through an agent or a comparison site, the allowance shown was the one attached to that specific fare at that moment. Check your confirmation email rather than the airline's general page.

Fees and where they hurt

Paying for a bag online in advance is nearly always cheaper than paying at the airport, and paying at the airport is nearly always cheaper than paying at the gate. The gap can be large. On some carriers the gate price is more than double the online price for the same bag.

Excess weight is charged per kilogram on many airlines, which is why a bag two kilos over can cost more than the fare seemed worth. A luggage scale at home is a cheap way to avoid the surprise, or weigh yourself on a bathroom scale holding the bag and subtract.

Restricted and prohibited items

Some items are banned outright, some are cabin-only, some are hold-only. The direction of the rule matters.

• Power banks and spare lithium batteries: cabin only, never in the hold
• Sharp objects and tools over a certain length: hold only
• Flammable liquids, most aerosols beyond personal care sizes, fireworks: not permitted at all
• E-cigarettes and vapes: cabin only, and usually must not be charged in flight

Sports equipment, musical instruments and mobility aids each have their own handling. Declare them when booking rather than arriving with a surfboard and optimism.

Fragile and valuable things

Airlines limit their liability for damage and loss, and that limit is usually well below the value of a laptop or a camera. Anything you would be upset to lose belongs in the cabin.

If you must check something fragile, pack it in the centre of the bag surrounded by clothing, and accept that a fragile sticker is a request rather than a guarantee.

Labelling, inside and out

Put a tag on the outside with your name and a phone number. Then put a card with the same information inside the bag. When an outside tag is torn off, the inside card is often what reunites the bag with its owner.

Photograph the bag before you travel. It takes two seconds and makes a lost baggage report much faster to file. Our guide on what to do when baggage goes missing explains the rest of that process.

One practical habit

Check the allowance twice: once when booking, and once about a week before departure. Airlines change published allowances more often than you would think, and a week gives you time to buy the extra bag at the online price instead of the counter price.