airline carry-on – From Southwest to American and international carriers, carry-on allowances depend on exact dimensions, fare type, and sometimes even weight limits. Here’s the practical guide travelers need before they pack—especially if you’re trying to avoid checking a bag.
For anyone who’s ever stood at the airport gate with a carry-on that’s “almost” within the limits. the stress is familiar: you’re juggling time. overhead-bin space. and the uneasy feeling that one inch could cost you a checked bag. Airlines don’t make it simple—carry-on permissions hinge on strict size measurements. what counts as a personal item. and sometimes fare type or route.
Most domestic airlines generally allow two items: one personal item that fits underneath the seat in front of you, and one larger carry-on bag for the overhead bin. Some basic economy fares reduce that to only one personal item.
In many cases, the size limits apply to the larger carry-on as a whole—including handles and wheels. As a rule of thumb, the common standard size limit across most domestic airlines for the larger carry-on is around 22 by 14 by 9 inches (length by width by height).
The same isn’t always true across airlines, though. Some carriers specify size requirements for both the personal item and the overhead bag. while others focus mainly on the overhead baggage. Either way. the line is clear: your larger carry-on is measured as the full bag. and the personal item must land in the space under the seat.
There are also items that typically don’t count toward your carry-on or personal item allowance. Coats, books, umbrellas, food purchased at the airport, duty-free items, diaper bags, infant car seats and strollers are generally treated as exempt from the count.
Southwest’s limits are among the most specific on dimensions. Carry-on items stored overhead must be no larger than 24 by 16 by 10 inches. The personal item—such as a briefcase. laptop computer case. backpack. pillow. blanket or camera—must fit under the seat in front of you. Neck pillows do not count toward the carry-on limit.
Delta Air Lines uses a combined measurement for the overhead bag: the combined length. width and height of carry-on baggage should be less than 45 inches. Individually. the overhead items must be less than 22 by 14 by 9 inches. while personal items must be small enough to fit under the seat in front of you.
American Airlines sets the overhead limit at no more than 22 by 14 by 9 inches. Personal items for American can measure up to 18 by 14 by 8 inches.
United Airlines is similarly strict for overhead luggage, with larger carry-on items limited to 22 by 14 by 9 inches. Under-seat personal items on United must measure no more than 17 by 10 by 9 inches.
JetBlue requires overhead items to be no larger than 22 by 14 by 9 inches. Personal items must measure less than 17 by 13 by 8 inches.
Alaska Airlines also caps overhead items at 22 by 14 by 9 inches, while personal items must fit underneath the seat in front of you.
Hawaiian Airlines uses the same overhead measurement—22 by 14 by 9 inches—and requires personal items to fit under the seat in front of you.
Not every travel day is treated the same once you step outside U.S. routes. For international carriers, carry-on size limits are more varied than they are domestically, and—just as importantly—economy passengers’ allowances can depend on fare type.
The difference between a carry-on and a personal item still matters, because airlines label them differently. If your bag fits under the seat in front of you. it’s considered a personal item; this includes small backpacks. purses. briefcases and laptop bags. Larger bags—including suitcases that fit in the overhead compartment—are treated as larger carry-on items.
Fare rules can shift what’s allowed too. Most domestic airlines generally permit one carry-on bag and one personal item free of charge, depending on fare type. But United’s cheapest fare type. basic economy. restricts flyers to one personal item that can fit under the seat in front of them. Ultra-low-cost carriers can be even tighter: if you book with Frontier Airlines or Breeze Airways. the basic fare only includes a personal item.
Southwest is a notable contrast in its own history. The airline once stood out for allowing passengers two free checked bags, a carry-on and a personal item regardless of fare type. In 2025, Southwest decided to end that allowance and start charging for checked baggage.
Weight is another place travelers get caught out, though the rules are inconsistent. For domestic airlines, many don’t list a blanket carry-on weight restriction. Some do enforce weight limits on specific routes. Delta restricts passengers flying to and from Beijing and Shanghai to a 22-pound carry-on. and it restricts bags to and from Singapore to 15 pounds. Low-cost airlines Frontier and Sun Country both have 35-pound limits. Hawaiian Airlines limits carry-on bags to 25 pounds.
International carriers, meanwhile, often specify carry-on weight requirements that vary by fare type. For economy fares. weight limits listed for major carriers include 15 pounds for Emirates. Singapore Airlines. Cathay Pacific and Qatar Airways. as well as Air New Zealand; 17 pounds for Turkish Airlines; 22 pounds for Virgin Atlantic. ANA. Korean Air and Japan Airlines; 39 pounds for La Compagnie; and 51 pounds for British Airways.
Even when your bag fits perfectly, what’s inside can still trip you up. In the U.S. the Transportation Security Administration monitors carry-on bags similarly to checked luggage and prohibits certain items. including firearms. lithium batteries and other potentially hazardous items outlined on TSA’s website. Liquids are limited by the 3-1-1 rule: containers must be less than 3.4 ounces. and they must fit in a quart-size bag.
TSA recommends packing full-size liquids in checked luggage. The safest place for valuables like purses, electronics, passports, jewelry and medicines is your carry-on.
For inbound international flights to the U.S. there’s a specific exception: liquids exceeding 3.4 ounces can be carried if purchased in the duty-free section and kept in secure. tamper-evident bags. Travelers should keep the original receipt because TSA may request proof the purchase was made within the preceding 48 hours. Other border agencies can have similar restrictions, so it’s important to check airline rules for the route.
If there’s one takeaway that keeps showing up across airlines and itineraries. it’s this: when you’re trying to avoid checking a bag. you can’t treat carry-on rules as universal. Domestic airlines generally let travelers carry two items—one personal item and one overhead bag—so long as they meet the airline’s dimension thresholds. International carriers, by contrast, vary by fare type, and weight limits may come into play.
That means the decision happens before you get to the airport. Measure the bag, confirm the allowance for your fare type, and don’t assume that “carry-on” means the same thing from one airline to the next.
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