Is a backpack a personal item? Size limits by airline

What counts as a personal item?

A personal item is the one small bag included with your ticket that goes under the seat in front of you, on top of any carry-on bag that goes in the overhead bin. Airlines describe it by example: a purse, a briefcase, a laptop bag or a backpack. If it fits the size limit and fits under the seat, it counts.

Delta, JetBlue, United, Southwest, Wizz Air, easyJet and British Airways name a backpack (or rucksack) outright. The other airlines in the table give a size or a few examples, and none of them excludes backpacks.

On budget fares the personal item is often the only free bag. Ryanair, Wizz Air, easyJet and Frontier include one under-seat bag with every ticket and charge for an overhead-bin bag, so the personal item size is the size you travel with.

Personal item size by airline

These are the personal item limits each airline published on its own baggage page, checked in early November 2026. Airlines change their limits, so confirm the size with your airline before you fly. Where an airline gives only one unit, we converted it to the other, and the converted figure is marked with an asterisk.

The narrowest limit in the table belongs to United. At 10 inches (25 cm), its middle measurement is 3 to 4 inches (8 to 10 cm) narrower than JetBlue’s or American’s, so a backpack that passes at JetBlue can fail at United.

The European full-service airlines share one size, 40 x 30 x 15 cm, and that is the smallest box in the table. The budget airlines Ryanair and Wizz Air allow 5 centimetres more depth, and easyJet allows the largest bag in Europe.

Delta, Southwest and Alaska publish no personal item size on their carry-on pages. Their rule is only that the bag fits under the seat in front of you, and the space under a seat changes with the plane and the seat. If you fly all three, a backpack within 17 x 10 x 8 inches (43 x 25 x 20 cm) is the safest choice, because it fits every published US limit in the table.

Personal item size compared with carry-on luggage size

A carry-on bag goes in the overhead bin and is much larger than a personal item. At American, United, Delta, Alaska and JetBlue, the carry-on luggage size is 22 x 14 x 9 inches (about 56 x 35 x 23 cm), wheels and handles included.

Southwest and Frontier allow a 24 x 16 x 10 inch carry-on. In Europe, the cabin bag is 55 x 40 x 23 cm at Lufthansa and Wizz Air, 55 x 35 x 25 cm at KLM, 55 x 40 x 20 cm at Ryanair, and 56 x 45 x 25 cm at easyJet and British Airways.

A large travel backpack of 35 litres or more is a carry-on, even when the airline would call a smaller backpack a personal item. The same backpack shape can be either one, and the measurements decide which.

What size backpack fits as a personal item?

A 20 litre backpack can fit the personal item limit of most airlines in the table, and a 30 litre backpack is too big for most of them. Multiply an airline’s three limits and you get the largest volume a bag can have and still fit. That number is a ceiling: only the largest limits come near 30 litres.

A backpack is rounder than a box and has straps and pockets on the outside, so a backpack always holds less than the box it fits in. The ceilings give three rules:

1. A backpack over 18 litres cannot fit the 40 x 30 x 15 cm limit at Lufthansa, British Airways, Air France and KLM. On those airlines, look for 15 litres or less.
2. A backpack over 24 litres cannot fit United, Ryanair or Wizz Air.
3. A backpack of 30 litres or more cannot fit any airline in the table except, in theory, American, easyJet and Frontier. Treat a 30 litre backpack as a carry-on.

Below each ceiling, the shape decides. A 20 litre backpack that is tall and thin can fail United’s 25 centimetre side, and a 20 litre backpack that is short and deep can fail the 15 centimetre limit in Europe. Litres measure what a bag holds inside. The airline measures the outside, with straps, pockets and handles included. Check the outside measurements on the product page before you trust the litre number.

Will my laptop fit in a personal item backpack?

A 13-inch or 15-inch MacBook Air fits inside every published personal item limit in the table. The longest side of a laptop is its width, and a 16-inch MacBook Pro is 35.6 centimetres wide and 24.8 centimetres deep, inside even the 40 x 30 cm limit. An 18-inch gaming laptop is too long for several airlines: the Alienware 18 below is 41 centimetres wide, longer than the 40 centimetre limit at Ryanair, Wizz Air and the European full-service airlines.

United has the smallest middle measurement, 25 centimetres. The 16-inch MacBook Pro is 24.8 centimetres deep, so it leaves less than 2 millimetres in total, and no backpack with padding around a 16-inch laptop can fit United’s limit. Some 16-inch gaming laptops are deeper than 25 centimetres and cannot fit at all.

Below are five laptops at true scale, from a 13-inch MacBook Air to an 18-inch gaming laptop. Scroll sideways to see them all.

The laptop also needs room around it. A backpack’s laptop sleeve sits inside the bag, behind padding and a zip, so the bag is always a few centimetres taller than the laptop. A 15-inch MacBook Air is 34 centimetres wide, which leaves about 6 centimetres for the bag around it inside a 40 centimetre limit. That is enough for a slim backpack and too little for a padded one.

Can a duffel bag be a personal item?

Yes, a small duffel bag can be a personal item if it fits the airline’s size limit and fits under the seat. The size rule decides for a duffel exactly as it does for a backpack. A soft duffel has one advantage over a backpack: a soft duffel squashes into the space under the seat more easily.

The risk is length. Most duffel bags are long and low, and a weekend duffel of 50 centimetres or more is longer than every personal item limit in the table. Look for a duffel no longer than 40 centimetres for Ryanair, Wizz Air, Lufthansa, British Airways, Air France and KLM, 45 centimetres for easyJet, and 17 inches (43 cm) for United and JetBlue.

Does a diaper bag count as a personal item?

On American, United and JetBlue, no: a diaper bag travels free on top of your personal item and carry-on. On Delta, the diaper bag counts as your personal item. Here is what each airline says on its own page:

• American Airlines does not count a diaper bag as a personal item or carry-on, with one diaper bag per child (American).
• United allows a diaper bag free on top of your personal item and carry-on, even when you travel without your child (United).
• JetBlue allows one diaper bag for a lap infant on top of the carry-on limit (JetBlue).
• Delta lists a diaper bag among its approved personal items. Delta’s children and infant items page lists a booster seat and a breast pump as extra free items, and no diaper bag. A baby travelling free on your lap has no baggage allowance of its own.

A diaper backpack follows the same rule as any diaper bag. If you fly Delta with a baby, pack it as your personal item and keep it small enough for under the seat.

See a personal item backpack next to a person and a suitcase

Measurements on a product page are hard to picture. Below is a flap backpack 43.2 centimetres tall, about 17 inches, at true scale next to a person, a cabin suitcase and a laptop.

At 43.2 centimetres tall, this backpack is exactly 17 inches, the longest side allowed by United and JetBlue, with no room to spare. It is 3.2 centimetres taller than the 40 centimetre limit at Ryanair, Wizz Air, Lufthansa, British Airways, Air France and KLM. Height alone rules those airlines out before anyone asks about depth.

For shops that sell backpacks and travel bags

Shoppers buying a backpack for flying ask one question before they order: will this count as my personal item? The litre number does not answer it, and neither does a line of measurements under the photos, because the shopper still has to compare three numbers with an airline’s three numbers in their head.

Tangiblee, a size visualization company, built Samsonite.com a feature that checks a bag against the carry-on rules of domestic and international airlines and compares it with a human-scale model. Tangiblee reports, in its Samsonite case study, 3 times the revenue per visitor for shoppers who used it and a 2.2 times higher likelihood to convert.

Shops that sell bags hear the same questions every week: will my laptop fit, will it fit under the seat, how big is it next to me. A bag shown next to a person, a laptop and a cabin suitcase answers all three in one look, on the product page and next to the photos.

EasySizes adds the size comparison above to a product page.

Personal item questions