Budget airline fees explained

A budget fare usually covers a seat on the flight and a small personal item, such as a handbag or small backpack that fits under the seat in front. Almost everything else, from a larger cabin bag to choosing a seat, may be an optional extra with its own price.

Fee names, prices and allowances vary between airlines and even between fare types on the same airline, and they change over time. Treat this guide as a checklist of what to look for, and always confirm the current rules on the airline's website for your specific booking.

Baggage is the most common surprise. Check three things for your fare: what counts as the free personal item, whether a larger cabin bag for the overhead locker is included, and what checked bags cost. Each has its own size and often weight limits.

Measure and weigh your bags at home. Airlines can charge extra at the gate for bags that are too large, and those charges are usually higher than adding the bag when you book. Adding a bag during booking is generally cheaper than adding it later.

Remember the security rules as well as the airline's. Liquids and certain items have their own restrictions at airport security, which differ by country; the official UK and US guidance is linked below.

On many low-cost airlines, seats are assigned for free at check-in, and choosing your own seat costs extra. If you are travelling alone and do not mind where you sit, the free option is usually fine.

Families and groups who want to sit together should check the airline's policy. Some airlines seat young children with an adult automatically; others expect you to pay. Priority boarding, sometimes bundled with a cabin bag, is another optional extra worth comparing against what you actually need.

Most low-cost airlines expect you to check in online within a set window before departure. Some charge for checking in at the airport or for printing a boarding pass there. Set a reminder for when online check-in opens and save your boarding pass on your phone or print it at home.

If you are travelling internationally, the airline may need passport details before check-in. Have your documents ready, and see our travel documents checklist for what to sort before you go.

Look at the final payment screen carefully. Some airlines or agents add fees for certain payment methods, and optional extras such as insurance may be offered along the way; only add what you want.

Basic fares often have strict rules on changes, with fees plus any difference in fare. Name corrections can also cost money, so check the spelling against your passport before paying. If your plans are uncertain, compare the cost of a flexible fare with the risk of paying change fees later.

To compare fares fairly, build the trip you will actually take on each airline: the same bags, seats if you need them, and any fees for check-in or payment. In the EU, the price shown must include all unavoidable taxes and charges, which helps, but optional extras still need adding to each option.

Then add the cost of getting to and from the airport. Our guide on how to find cheap flights explains this total-cost approach in more detail, and our list of cheap flight tips covers ways to avoid many of these fees altogether.

Most unexpected charges happen at the airport, when it is too late to compare prices. Before you leave home, check that your bags meet the size and weight limits for your fare, that you have checked in online if the airline requires it, and that your boarding pass is saved on your phone or printed.

Arrive with enough time to queue for bag drop and security, especially at busy times. If a bag is close to the limit, wear your heaviest items or move them to your personal item rather than risk a gate fee. If you are unsure about a rule, the airline's website is the final word, not a comparison site.

Keep your booking confirmation and any receipts for extras. If you are charged something you believe you already paid for, it is much easier to resolve with the paperwork to hand.