Carry-on sizer rules by airline (2026)
A bag that works on one airline may be too large on another. This page helps you compare your bag against published size rules and spot the bag types most likely to get questioned at the gate.
Compare your bag to published carry-on dimensions
Enter the outside dimensions including wheels, handles, and stuffed pockets. This tool only compares against published airline dimensions. It does not guess missing airline rules or promise that airport staff will handle every bag the same way.
A 22 × 18 × 10 inch bag fails 4 published sizer rules in this comparison.
This checks size only. A bag can still be challenged if it is rigid, visibly overpacked, too heavy, or used on a stricter fare.
Cabin bag matches
Published limit: 17.7 in × 14.2 in × 7.9 in. Every fare includes one small underseat bag up to 45 x 36 x 20 cm and 15 kg, if the traveler can lift it
Personal item / small-bag matches
Published limit: 18 in × 14 in × 8 in. Every fare includes one personal item; boarding checks can trigger charges if it exceeds 8 x 18 x 14 in
Published limit: 22 in × 14.2 in × 9.1 in. Economy and Premium Economy include 1 carry-on item up to 56 x 36 x 23 cm and 7 kg, plus a small personal item.
Published limit: 22 in × 14.2 in × 9.1 in. Business and First include 2 carry-on items, each up to 56 x 36 x 23 cm and 7 kg, plus a small personal item.
Enforcement risk tiers
Start here to decide how cautious to be before you pack. Stricter airlines are more likely to notice rigid, overstuffed, or borderline bags.
| Group | Typical published carry-on | What to watch for | Risk |
|---|---|---|---|
| US Big Three (UA / DL / AA) | 22 × 14 × 9 (common baseline) | Full flights make rigid rollers more likely to get checked | Medium |
| US low-cost carriers (Spirit / Frontier) | Personal item is included; larger bags usually cost extra | A bag that looks too large is more likely to be checked against the sizer | Extreme |
| European low-cost carriers (Ryanair / easyJet) | Personal item baseline + paid “large cabin bag” | Buy the correct bag option before travel if your bag needs the overhead bin | Extreme |
| Regional flights (small jets) | Overheads + under-seat are physically smaller | Tags can reroute bags to carousel; under-seat obstructions exist on some aircraft | High |
What triggers checks
On busy flights, agents often pre-tag rigid rollers because they do not compress. Soft bags are less likely to draw attention because they look smaller and can squeeze into tighter spaces.
Some airports do not use obvious metal sizers every time. If the bag looks too large, staff may ask you to check it even before exact measuring starts.
Small aircraft have real physical limits. Even if carry-on bags are allowed, you may still be forced to gate-check. Keep medicine, keys, and documents with you in case the bag is sent to the carousel.
On airlines where the cheapest fare includes only a small bag, choose a personal item that can compress into the sizer even when it is packed.
Recommended gear
These bag types are easier to fit into sizers and under seats. Where a product link is available, it appears below.
Next: choose the cheapest workable bag plan
If your bag is close to the limit, compare the airline rule with the fare you plan to buy. A Basic fare or low-cost carrier may make a checked bag cheaper than gambling on an oversized cabin bag at the gate.