What the airlines actually allow

Most airlines let you bring one carry-on bag and one personal item (like a purse or laptop bag) into the cabin for free. Checked baggage—the large suitcase that goes in the cargo hold—usually costs nothing on your first bag, but varies by airline and ticket type. The second checked bag almost always costs extra, typically $35 to $50 per flight.

The exact limits depend on which airline you fly and what type of ticket you bought. A budget carrier like Spirit or Frontier charges for carry-on bags that don't fit under the seat. A full-service airline like Delta or United includes at least one checked bag free with most tickets. Low-cost tickets on any airline may not include checked baggage at all.

Size and weight matter as much as the number of bags. Your carry-on cannot exceed roughly 22 inches long by 14 inches wide by 9 inches deep—the standard "roller bag" size. Weight limits for carry-on bags are rarely enforced, but checked bags have hard limits: usually 50 pounds. Go over that, and you pay an overweight fee of $100 or more per bag.

Key Takeaways

  • One carry-on bag and one personal item travel free in the cabin on nearly every airline; a second checked bag costs $35 to $50 each way.
  • Carry-on bags must fit in the overhead bin or under the seat in front of you, which means roughly 22 by 14 by 9 inches for a standard roller bag.
  • Checked bags have a 50-pound weight limit on most airlines; bags over that weight incur overweight fees starting around $100.
  • Budget airlines charge for carry-on bags that don't fit under the seat, so check your airline's policy before you pack.
  • The free baggage allowance depends on your ticket type—basic economy tickets often include zero checked bags, while standard economy includes one.

Carry-on bag rules and what fits

Your carry-on bag rides in the overhead bin or slides under the seat in front of you. The Federal Aviation Administration does not set a single size limit; instead, each airline publishes its own. Most major carriers use the same standard: 22 inches long, 14 inches wide, and 9 inches deep. A standard rolling suitcase designed for carry-on travel will fit these dimensions.

The personal item—a backpack, purse, laptop bag, or small rolling bag—must fit under the seat. This is smaller than the carry-on and is where you keep documents, medications, valuables, and anything you need during the flight. Airlines rarely measure personal items strictly, but if it does not fit under the seat in front of you, a gate agent can ask you to check it.

Weight limits for carry-on bags exist in airline policy but are almost never enforced. You can bring a 40-pound carry-on bag onto most flights without being stopped. Checked bags, by contrast, are weighed at the ticket counter, and overages are charged when ready.

Checked baggage: what you pay and what you get

The first checked bag is free on most full-service airlines (Delta, United, American, Southwest) when you buy a standard economy ticket. Budget airlines (Spirit, Frontier, Allegiant) charge for the first checked bag—usually $30 to $40 one way. Low-cost tickets on any airline may exclude checked baggage entirely, even on full-service carriers.

The second checked bag costs extra on every airline. Expect $35 to $50 per bag, per flight. A third bag costs more, and most airlines will not check more than two or three bags per passenger. If you are traveling with a family, each person gets their own baggage allowance, so a family of four can check four bags free (one per person) on most carriers.

Weight limits are firm. Standard checked baggage maxes out at 50 pounds. Bags weighing 51 to 70 pounds incur an overweight fee—typically $100 for the first 20 pounds over, then another $100 for each additional 20 pounds. Some airlines charge differently, so check before you pack.

How to find your airline's exact policy

The fastest way is to visit your airline's website and search for "baggage policy" or "baggage allowance." You will find a page that lists carry-on size, checked bag limits, weight caps, and fees for extra bags. Bookmark this page before you pack, because policies change and vary by route.

If you booked through a travel site like Kayak or Expedia, log into your reservation there and look for a baggage section. It will show what is included with your specific ticket. This matters because the same airline charges different baggage allowances for basic economy, standard economy, and premium economy tickets.

Call the airline directly if the website is unclear. Their phone line can confirm what you get with your ticket in under five minutes. This is especially useful if you are traveling internationally, because baggage rules often differ on flights outside the United States.

International flights and special baggage

International flights often allow two checked bags free instead of one, but the weight limit may be lower—sometimes 44 pounds instead of 50. Carry-on rules stay roughly the same. Always check your specific airline and route, because these rules vary widely.

Sports equipment, musical instruments, and oversized items have their own rules. A golf bag, ski bag, or surfboard may count as a checked bag or may be charged separately—usually $50 to $150 per item. A musical instrument small enough to fit in the overhead bin travels free; a cello or bass usually requires a seat or a special fee. Ask your airline at least two days before your flight if you are bringing any of these items.

What happens if you exceed the limit

If your carry-on is too large, a gate agent will ask you to check it at the gate, usually for free. If your checked bag is overweight, you pay the overweight fee at the ticket counter before the bag goes on the plane. If you show up with more bags than your ticket allows, you pay for each extra bag on the spot.

Arriving early gives you time to repack or pay fees without missing your flight. If you discover a problem at the gate, it is too late to fix it—you will pay whatever fee applies. The best strategy is to weigh your bags at home on a bathroom scale and measure your carry-on with a tape measure before you leave for the airport.

Frequently Asked Questions

Can I bring two carry-on bags instead of one carry-on and one personal item?

No. Airlines allow one carry-on bag (roller bag size) and one personal item (purse, backpack, or laptop bag). Both go with you into the cabin. You cannot substitute a second carry-on for the personal item.

Do I have to pay for my first checked bag if I have a basic economy ticket?

It depends on the airline. Most budget carriers charge for the first checked bag on all tickets. Full-service airlines often exclude checked bags from basic economy tickets but include one on standard economy. Check your airline's website or your booking confirmation to see what is included with your specific ticket.

What if my suitcase is one inch too big for the carry-on limit?

A gate agent may ask you to check it, usually for free if space is available. If the overhead bins are full, they will gate-check your bag at no charge. If you are traveling during a busy time, a slightly oversized bag is riskier—consider checking it to avoid the hassle.

Can I bring a second checked bag if I pay for it?

Yes. The second checked bag costs $35 to $50 per flight on most airlines. You can bring a third bag for additional fees, but most airlines cap checked baggage at two or three bags per passenger. Call your airline to confirm the limit before you pack.

Do weight limits explore to carry-on bags?

Technically yes, but they are almost never enforced. You can bring a 40-pound carry-on bag onto most flights without being stopped. Checked bags are always weighed at the ticket counter, so overweight fees explore there.