These are commonly cited limits for each airline's standard cabin bag allowance and can change without notice — always confirm on your airline's current baggage policy page before flying, especially on budget carriers with strict enforcement.
There is no single global standard for cabin baggage dimensions, which surprises a lot of travellers who assume a bag marketed as "carry-on approved" will be accepted everywhere. In reality every airline sets its own maximum length, width and height, and budget carriers in particular have grown noticeably stricter over the years, often shrinking their free personal-item allowance while charging extra for anything closer to a traditional carry-on size. A bag that has sailed through security on a dozen full-service airline flights can still be gate-checked or charged as oversized on a budget carrier with a smaller sizing cage at the gate.
Enter your bag's three dimensions and this tool compares them, in every possible orientation, against a set of commonly cited allowance categories — a typical full-service airline, a typical domestic US carrier, and several budget carrier tiers that have become common across different regions. Bags are compared by their largest, middle and smallest dimension rather than assuming length, width and height must line up in one fixed order, since sizing cages at the gate check volume across all three dimensions rather than caring which specific side is labelled "length."
Airlines, especially budget carriers, discovered that separating a genuinely small personal item allowance from a larger paid cabin bag allowance creates a new source of ancillary revenue, and that shift has been widespread across the industry over the past several years. This is why some airlines now show two very different size categories in their published policy — a small free "personal item" and a noticeably larger paid "cabin bag" — and travellers who don't check which category their fare includes are the ones most likely to be caught out at the gate.
Gate agents on strict carriers typically use a physical sizing cage or frame, and a bag that doesn't fit is usually charged a checked-bag fee on the spot, often at a premium rate compared with pre-booking a checked bag online in advance. This is one of the more expensive and avoidable travel costs, entirely preventable by checking your bag's actual dimensions against your specific airline's specific published limit before you ever reach the airport.
Measure the bag itself, including wheels, handles and any external pockets when expanded, since most airlines' stated limits include these protruding parts even though it's tempting to measure only the main body. A bag that measures within limits with wheels retracted but exceeds them with wheels extended is a common way travellers get an unpleasant surprise at a strict gate check, so always measure the bag exactly as it will look when you're carrying it to the gate.
A final tip: if you're between two bag sizes while shopping for new luggage, sizing down tends to be the safer long-term choice, since airline cabin allowances have generally been trending smaller and stricter over recent years rather than more generous.
No — the categories here are commonly cited general allowances; the same airline can vary limits by fare class, route, or region, and policies change over time. Always confirm the exact current limit on your specific airline's baggage policy page for your booked fare.
Yes, measure the bag exactly as it will be carried to the gate, including wheels, handles and any external pockets, since most airlines' published limits already account for these parts.
A personal item is typically a small bag like a handbag or laptop bag meant to fit under the seat in front of you, usually included free even on strict budget fares. A cabin bag is larger and meant for the overhead bin, and on many budget carriers now costs extra or requires a higher fare tier.
Yes, size and weight are enforced separately by many airlines, particularly budget carriers, so check both the Luggage Weight Calculator and this size checker rather than assuming one covers the other.