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Personal item size limits by airline

The free bag that fits under the seat in front of you has its own size limit — and it's how you fly a basic-economy fare without paying for a carry-on. Here are the published limits.

By Stephen V.Updated How we test

A personal item is the smaller bag that fits under the seat in front of you, and on most airlines it is free — even on basic-economy fares that charge for a carry-on. US carriers cluster around 18 x 14 x 8 inches, but the exact limit varies, and a few airlines only say "it must fit under the seat" without publishing dimensions. The table below has the published numbers.

This is the single best money-saving trick in air travel: on a basic-economy fare, a personal item that fits the under-seat space flies free while a carry-on costs extra. A wheeled underseat bag or a carry-on backpack sized to these limits is how you do it.

US airlines — personal item limits

AirlineMax dimensions (in)Notes
American Airlines18 x 14 x 8Free on all fares
Delta Air LinesNo strict published sizeMust fit under the seat
United Airlines17 x 10 x 9Free; carry-on not included on Basic Economy
Alaska AirlinesNo strict published sizeMust fit under the seat
JetBlue17 x 13 x 8Free on all fares
Southwest18.5 x 8.5 x 13.5Free, plus a full carry-on
Frontier14 x 18 x 8Free; carry-on costs extra
Spirit18 x 14 x 8Free; carry-on costs extra

Figures as published by each carrier for the free under-seat personal item. Where an airline does not publish strict dimensions, the rule is simply that the bag must fit fully under the seat in front of you. Confirm on the carrier's baggage page (linked below) before you fly.

How to use the personal-item allowance

The trick is buying a bag sized to the smallest limit you expect to fly (United's 17 x 10 x 9 in is a common tight one) so it works everywhere. A structured underseat roller maximizes the space and rolls; a travel backpack that compresses is more flexible and hands-free. Either way, our packing guide gets more into it than you would think.

Questions

Frequently asked

What is a personal item on a flight?
It is the smaller bag that fits under the seat in front of you — a backpack, purse, laptop bag or small underseat roller. On most airlines it is free, even on basic-economy fares that charge for a carry-on.
What size personal item works for all airlines?
Aim for around 17 x 10 x 9 inches (United's tighter limit) or smaller and it will fit almost every carrier's under-seat space. Bigger bags may fit some airlines but not all.
Can I bring a personal item and a carry-on?
On standard fares, usually yes — one personal item plus one carry-on. On basic-economy fares (Frontier, Spirit, United Basic Economy) the carry-on often costs extra while the personal item stays free.
Does a backpack count as a personal item?
Yes, if it fits under the seat within the airline's limit. A compressible travel backpack is one of the best personal items because it squeezes into tight under-seat spaces.

Keep reading

Related

Receipts

Sources

We do not run a testing lab, and we do not pretend to. Specifications come from the manufacturer's own listing or manual, and size and weight limits from the airline's official baggage-policy page. Where we could not verify something, we say so on the page rather than quietly leaving it out. Read our full method.