Nothing ruins the start of a trip like being stopped at the gate because your carry-on is two centimetres too tall. Airlines have tightened enforcement in 2026, with more gate checks, more sizers at boarding, and fees of $65 to $100 for bags that do not fit. The problem is that there is no universal standard: a bag that fits perfectly on one airline is too big for another, and budget carriers often allow less than half the size of a full-service airline. This guide compares the carry-on limits of 20 major airlines, explains the personal item rules, and shows you how to pack so your bag always fits.

Most full-service airlines allow a carry-on of 56 x 36 x 23 centimetres, including wheels and handles. That standard covers British Airways, Lufthansa, Air France, Emirates, Qatar Airways, and Singapore Airlines, though weight limits vary from 7 to 12 kilograms. US carriers are more generous on size: American, Delta, and United allow 56 x 35 x 23 centimetres with no published weight limit, though the bag must be liftable into the overhead bin. Budget airlines are far stricter. Ryanair allows only 40 x 20 x 25 centimetres free, with larger bags costing extra, and easyJet allows 45 x 36 x 20 centimetres. Wizz Air allows 40 x 30 x 20 centimetres. Always measure your bag including wheels and handles, because airlines measure the same way, and a bag that is 56 centimetres without wheels is often 59 with them.

Almost every airline allows a second, smaller personal item for free, but the size varies. The typical limit is 40 x 30 x 15 centimetres, roughly the size of a small backpack or a large handbag, and it must fit under the seat in front of you. Some airlines are generous: JetBlue and Southwest allow a personal item plus a carry-on on all fares. Budget carriers are the exception: Ryanair's free allowance is only the personal item, and a larger cabin bag costs extra, while Wizz Air charges for anything beyond the small personal item. The practical trick is to pack your valuables, electronics, and a change of clothes in the personal item, so that even if your carry-on is gate-checked, you keep the essentials with you. A compressible packing cube helps the personal item fit under seats that vary in size between aircraft.

Measure your bag at home with a tape measure, including every protruding part: wheels, handles, and external pockets. If the bag is even one centimetre over, it can fail the sizer test at the gate. Soft-sided bags have an advantage here, because they can be compressed into the sizer, while hard-shell cases cannot. Pack heavy items at the bottom near the wheels, which keeps the bag stable and easier to lift. Use packing cubes to compress clothes, and wear your bulkiest jacket and shoes onto the plane rather than packing them. If your bag is close to the limit, remove the contents and weigh it empty first; many bags weigh 3 to 4 kilograms empty, which eats into a 7-kilogram limit before you pack a single shirt.

Gate fees are the most expensive way to deal with an oversized bag, so prevention is everything. Check your airline's limits before you pack, not at the airport. If your flight is full, the airline may ask for volunteers to gate-check bags for free; volunteering early gets you a free checked bag and a faster boarding experience. Board early if you can, because overhead bin space runs out on full flights and late boarders get their bags checked regardless of size. If you fly budget airlines regularly, invest in a bag designed to their exact limits: several manufacturers now sell Ryanair and easyJet specific cabin bags. Finally, keep your boarding pass and bag tag accessible, because gate agents check both, and a calm, prepared traveller is far less likely to be singled out for a sizer test.

What is the standard carry-on size? Most full-service airlines allow 56 x 36 x 23 centimetres, but budget airlines allow much less. Do US airlines have a carry-on weight limit? American, Delta, and United do not publish one, but the bag must be liftable into the bin. International carriers usually limit carry-ons to 7 to 10 kilograms. Does a personal item count separately? Yes, most airlines allow a personal item in addition to a carry-on, but budget carriers may charge for the carry-on. What happens if my bag does not fit the sizer? You will pay a gate fee, typically $65 to $100, and the bag will be checked. Are wheels included in the measurement? Yes, airlines measure the bag including wheels, handles, and pockets.