Most airlines allow two cabin items: a personal item that fits under the seat in front of you and a carry-on that goes in the overhead bin. They are measured separately, and they have different jobs.
Definitions in practice
| Personal item | Carry-on | |
|---|---|---|
| Where it goes | Under the seat in front | Overhead bin |
| Typical size | Roughly 43 × 33 × 16 cm at larger carriers | Roughly 55 × 40 × 23 cm |
| Access in flight | Easy, at your feet | Difficult; stored overhead |
| Best for | Documents, tech, snacks, a layer | Clothes and toiletries |
What actually fits under a seat
The depth limit is the tight one. A personal item that is 16 cm deep is thin: think slim daypack, tote or messenger, not a stuffed 20-litre backpack. Many popular daypacks are 20+ cm deep when full, which is why we list size on every bag and let you filter by airline in the Bag Finder.
What to pack in each
- Personal item: passport, boarding pass, phone, power bank, headphones, a book or e-reader, medications, a light sweater, a water bottle to fill after security.
- Carry-on: the bulk of your clothes, shoes, a toiletry kit within liquid limits, and anything you will not need in flight.
When you only get one
Some cheaper fares include only a personal item. In that case, treat it as your only bag: choose a soft, squeezable bag, wear your bulkiest layer, and use compression to save space. A 20-litre soft bag can carry a surprising amount if you plan around it, but check the depth against the airline’s limit first.
Choosing a personal item bag
Look for a slim profile, a lay-flat main compartment, a bottom that does not bulge, and enough organization to find your passport without unpacking. For comparison, see our underseat picks:
| Bag | Size (cm) | Capacity | Weight |
|---|---|---|---|
| 43 × 28 × 13 cm | 13 L | Not listed | |
| 40 × 25 × 20 cm | 20 L | Not listed | |
| 50 × 28 × 24 cm | 20 L | Not listed |
Sizes are manufacturer-listed. Verify them against your airline before you buy.
Frequently asked questions
Can I bring a backpack and a carry-on suitcase?
On fares that include both, yes: the backpack must fit under the seat and the suitcase goes overhead. Check your fare, because cheaper fares may include only one.
Is a purse a personal item?
Yes, on most airlines a handbag counts as a personal item, though some airlines count it separately from a larger bag. Check the airline’s wording.
Where should I keep my medications?
In the personal item, within reach. Carry prescription medication in its original packaging.
Information here is general and can go out of date. Confirm airline rules with the airline before you travel. See our methodology.
