United Carry On Dimensions: Exact Limits and Measuring

22 x 14 x 9 inches (55.88 x 35.56 x 22.86 cm) is the maximum size for one carry-on bag stored in the overhead bin, on every United fare except domestic Basic Economy. That's 45 linear inches if you add the three numbers together, though United doesn't publish it as a combined linear-inch rule the way Delta does. It states three separate maximum dimensions instead, and your bag has to clear all three, not just the total.

There's no published weight limit for a United carry-on. The only real-world constraint is that you need to be able to lift the bag into the overhead bin yourself, since gate agents won't do it for you. If you're not sure your bag actually measures 22 x 14 x 9 including its wheels and handle (a lot of 'carry-on sized' luggage runs a little over), run it through the fit checker on this site before you fly rather than finding out at the gate.

Separately from the carry-on, United allows one personal item that fits under the seat in front of you: purses, backpacks, and laptop bags in this category. United's stated maximum is 17 x 10 x 9 inches. That's smaller and narrower than the carry-on allowance, particularly on width, so a backpack that just barely clears the carry-on sizer will not pass as a personal item.

The personal item is included on every United fare, including Basic Economy. It's the one bag Basic Economy passengers can count on bringing into the cabin for free, which is why so many Basic Economy flyers end up traveling with a slightly oversized 'personal item' packed to its absolute limit instead of a real carry-on.

On most domestic and short-haul United Basic Economy tickets, you can only bring the personal item on board. A full carry-on is not allowed in the cabin. United's own wording is direct: in Basic Economy, you can only bring one personal item on most flights, and carry-on bags are prohibited except on routes to South America and across the Atlantic or Pacific. If you show up at the gate with a carry-on on a route where it isn't included, you'll have to check it.

There are exceptions. Basic Economy passengers flying to South America, or on transatlantic or transpacific routes, do get the full carry-on allowance. MileagePlus Premier members and holders of qualifying United co-branded credit cards also keep the full carry-on regardless of fare. If none of those apply to you and you're flying domestic Basic Economy, plan around the personal item only, or upgrade to a standard fare before you pack a rolling bag.

Not for the allowance itself. If your fare includes a carry-on, United doesn't charge extra to bring it, the same way it doesn't charge for the personal item on any fare. What you do get charged for is a disallowed bag on Basic Economy that has to be checked at the gate instead of carried on: for tickets purchased on or after April 3, 2026, that's $50 if you check it in the airport lobby and $75 if you check it at the gate, versus $40 and $65 for tickets bought before that date. That's a different charge than a standard checked bag fee, and it exists specifically because your carry-on wasn't allowed in the cabin in the first place.

As for a normal checked bag on a standard fare, United does not publish one flat number. Its own checked-bags page says fee changes depend on when you bought your ticket and where you're flying, and points you to its baggage fee calculator instead of a fixed rate card. Anyone quoting you an exact United checked bag price without checking the calculator for your specific route and ticket date is guessing.

What United does publish as fixed numbers are the size and weight ceilings around that fee. A standard checked bag can weigh up to 50 lb and measure up to 62 total inches (length plus width plus height, including handles and wheels). United won't accept a bag heavier than 100 lb or larger than 115 total inches at all, musical instruments aside. It also confirms extra charges apply once you're over the standard weight or size, and again over the pricier oversized/overweight tiers, without stating what those charges are on the page itself, so the calculator is genuinely the only place to get a real number.

United's approach to Basic Economy carry-ons is stricter than most of its direct competitors. Delta's Main Basic fare includes the same full carry-on and personal item as every other Delta fare, with no cabin-bag restriction at all. American's Basic Economy also allows a full carry-on and personal item, though American does flag that Basic Economy boards last, so overhead bin space may already be full by then. Alaska's Saver fare, its lowest tier, likewise keeps the full carry-on included.

United is the outlier among that group specifically because its Basic Economy drops the carry-on down to personal-item-only on most domestic routes. If you're comparing basic fares across airlines and carry-on space matters to your trip, that's the one difference worth checking before you book, not just the ticket price.