Personal Item Size: What Fits Under the Seat on U.S. Airlines

This guide is for travelers choosing a backpack, tote or underseat bag, especially on fares where the personal item is the only free bag.

Most U.S. airlines let you bring two things on board: a carry-on for the overhead bin and a smaller personal item that goes under the seat in front of you. The personal item has its own size limit, it isn’t the same on every airline, and on some flights it’s the only bag you can keep with you. Here’s how the limits compare, what counts as a personal item and what doesn’t, and how to measure a backpack or tote before you get to the gate.

The quick answer

There’s no single industry size. As listed by each airline on November 9, 2026:

If you fly more than one airline, our advice is to shop for the smallest limit you’re likely to face. A bag that fits JetBlue’s 17 × 13 × 8 inches also fits American’s 18 × 14 × 8.

Airline by airline

American Airlines

American allows one personal item and one carry-on bag. It describes the personal item as something like a purse or small handbag that fits under the seat in front of you, with a maximum of 18 × 14 × 8 inches (45 × 35 × 20 cm).¹

On regional flights operated as American Eagle, American says a carry-on larger than the personal-item size has to be valeted at the gate, at no charge.¹ Our advice: on a small regional jet, the personal item is the bag you’ll actually have at your seat, so pack it with that in mind.

JetBlue

JetBlue allows one carry-on and one personal item on all fares. Its personal item limit is 17 × 13 × 8 inches and the bag must fit under the seat in front of you. Its examples are a purse, small backpack, briefcase or laptop.²

JetBlue sets no weight limit on carry-ons, as long as you can lift the bag into the overhead bin yourself when no help is available.²

Delta

Delta allows one carry-on and one personal item. Instead of dimensions, it lists examples: a purse, briefcase, small backpack, belt bag or fanny pack, camera bag, diaper bag, laptop bag, or a similar item that fits under the seat.³

On Delta Connection flights with 50 seats or fewer, Delta says only personal items are allowed on board. Larger bags can be checked at the gate for free with a pink Gate Claim tag and handed back at the aircraft door.³

Budget airlines

Many people search for Frontier and Spirit personal item sizes in particular, because those airlines charge for a full-size carry-on on many fares. We couldn’t verify their current limits from their own pages for this update, so we don’t list a number. Our advice: check the airline’s own baggage page on the day you book, and measure against it. A common “18 × 14 × 8” bag is a good starting point, but don’t assume it fits every airline.

What doesn’t count as your personal item

Some things ride free, on top of your personal item and carry-on.

American lists diaper bags (one per child), breast pumps, small soft-sided coolers of breast milk, child safety seats, strollers, and medical or mobility devices.¹

Delta lists a jacket or umbrella, food or drink bought after security, a duty-free bag, and strollers, wheelchairs, child safety seats and assistive devices.³

JetBlue lists assistive devices, a reasonable amount of duty-free items, one diaper bag for a lap infant, and items like a coat, umbrella or infant car seat.²

Our advice: a coat doesn’t count, so wear the bulky one instead of packing it.

Is a backpack a personal item?

Yes, if it’s small enough. JetBlue and Delta both name a small backpack as an example.²³ The catch is depth: a soft backpack can measure 8 inches empty and 11 inches stuffed.

Our advice for a personal-item backpack:

• Look for listed outside dimensions at or under the smallest limit on your trip.
• Choose one with a flat back panel and a fairly square shape; round, tapered packs waste space under the seat.
• Avoid big outside water-bottle pockets that stick out once filled.
• A clamshell opening makes it easier to pack to the edges without overstuffing the middle.

How to measure a personal item

1. Pack it the way you’ll travel.
2. Measure height, width and depth at the widest points, including pockets, feet and handles that stick out.
3. Compare each number with the airline’s limit, not just the total.

Soft bags squeeze, but a stuffed front pocket can push a bag over the depth limit. Our advice: if you’re close, put the laptop and liquids in last, where you can reach them quickly, and leave the front pocket empty.

Personal item vs. carry-on

The personal item doesn’t replace your carry-on allowance, and a carry-on doesn’t count as a personal item. Delta notes that FAA rules require carry-on items to fit under a seat or in an enclosed storage compartment, and that staff can limit carry-on bags on full flights.³ If you’re buying one bag for both roles, see our carry-on size guide.

What to keep in your personal item

Our advice: assume your carry-on might be gate-checked, and pack the personal item so you could live without the bigger bag for a few hours.

• ID, passport and boarding pass.
• Medicine, glasses and contact lens supplies.
• Phone, chargers and any power bank; spare lithium batteries have to travel in the cabin. See our power bank rules.
• Your quart-size liquids bag, so it’s easy to pull out at security. See our TSA liquids guide.
• Keys, valuables and anything fragile.

Shopping checks for an underseat bag

• Listed outside dimensions, not just “fits under most seats.”
• A shape that keeps its size when full.
• A trolley sleeve if you’ll stack it on a rolling suitcase.
• A separate pocket for liquids, a laptop and your ID.
• Wheels only if you need them: wheeled underseat bags lose some packing space to the wheel housing.

Before you fly

• Look up the personal-item limit for every airline on your trip.
• Measure your bag packed.
• On small regional planes, expect the personal item to be your only bag at your seat.
• Keep essentials, medicine and batteries in it.