Baggage Rules Explained, Sizer By Sizer

Two different bags, two different rules

Low-cost carriers split hand luggage into two categories: a small personal item that travels free under the seat, and a larger cabin bag that on Ryanair and Wizz Air now costs extra unless you have paid for priority boarding. The free personal item allowance is genuinely small, Ryanair caps it at 40 x 20 x 25 centimetres, which rules out most standard daypacks bought before 2023.

The paid cabin bag allowance is roughly the size of a normal carry-on, around 55 x 40 x 20 centimetres on Ryanair and similar on Wizz Air, but it goes in the overhead locker only if you have paid for priority; otherwise it gets tagged and put in the hold for free at the gate on a full flight, which is often the outcome anyway.

The sizer cage is not negotiable

At gates in Stansted, Bergamo and Katowice, staff will physically walk your bag to a metal or plastic sizer cage if it looks borderline. If it does not slide in without force, you pay the oversized bag fee on the spot, which runs 45 to 60 euros on most Ryanair routes and is considerably worse than paying for the cabin bag allowance online in advance.

Soft-sided bags compress; hard-shell cases do not. A 45-litre soft backpack packed loosely will usually pass a sizer that a rigid 40-litre suitcase would fail, simply because fabric gives and plastic corners do not.

Checked baggage weight limits by carrier type

• Ryanair and Wizz Air: 20kg standard checked bag, with per-kilo overage fees that escalate fast past the limit.
• Legacy European carriers like Lufthansa and Air France: typically 23kg per bag in economy, sometimes two bags on long-haul fares.
• US carriers on transatlantic routes: usually 23kg per checked bag included in economy on international itineraries, unlike their punishing domestic basic economy policies.
• Gulf carriers such as Qatar Airways: often a generous 30kg in economy on many fare classes, worth checking before assuming the worst.

Special items and the rules people forget

Liquids over 100ml in carry-on remain banned across the EU and UK despite years of promised relaxation tied to new CT scanners; some airports, including a handful of terminals at Shannon and a few in Italy, have quietly moved to 2-litre allowances with the new scanners, but do not count on it at your specific gate. Check the airport's own website, not a general rule of thumb.

Battery packs above 100Wh, roughly the size found in laptop-charging power banks over about 27,000mAh, need airline approval and must travel in carry-on, never in checked luggage, on every carrier operating out of the EU and UK.

Packing to survive the sizer

1. Weigh before you leave home. A cheap luggage scale costs less than one overage fee and removes the guessing entirely.
2. Wear your heaviest items. Boots and a coat worn onto the plane do not count toward cabin bag weight or size on any carrier.
3. Compress soft bags. Compression cubes buy real centimetres on a soft-sided backpack, often enough to clear a strict sizer.
4. Screenshot your allowance. Have your booked cabin bag confirmation ready to show if a gate agent questions your bag.

In short

Baggage fees look punitive but they follow a simple logic: airlines are selling cabin space, not doing you a favor. Learn your specific carrier's dimensions, buy the allowance you need in advance, and the sizer cage becomes a formality rather than a 55-euro surprise at the gate in Bergamo.