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CarrySizer

Multi-airline trips

Route Compliance Checker

Add each operating airline on your itinerary and see the one bag size that survives the whole route. The strictest segment sets the safe packing limit.

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How the route verdict is built

Operating carrier first

Codeshares are risky because the marketing airline may not enforce the bag rule. Add the airline that operates each segment.

Segment-by-segment limits

Each leg can have its own cabin class, size limit, personal-item rule, and weight allowance. One oversized leg is enough to fail the route.

Strictest safe target

If one airline allows 23 cm depth and another allows 20 cm, the route recommendation is 20 cm. The looser segment does not cancel the tighter one.

Frequently asked questions

How do carry-on rules work when I fly with two different airlines?

Each airline on your itinerary enforces its own limits at its own gate, so your bag has to satisfy the strictest airline on the whole route. A bag that's fine on one leg can still be turned away on the leg with the smallest size or weight limit.

Which leg of a multi-airline trip decides my maximum bag size?

The leg with the smallest allowance. For example, flying Lufthansa (55×40×23 cm) and then Ryanair (55×40×20 cm), you have to pack to Ryanair's 20 cm depth — the tighter of the two. The route checker highlights this strictest limit for you.

Does a codeshare or partner flight use the operating airline's rules?

Yes. Carry-on allowance is set by the airline that actually operates each flight, not the one that sold the ticket. Check the operating carrier for every segment and add it separately above.

Keep exploring

Rules can change. Always verify with your airline before flying.