What Size Carry-On Is Allowed? Airline Size Limits

The Standard Size: 22 x 14 x 9 Inches

If you're flying American, Delta, United, JetBlue, or Alaska, the carry-on size limit is 22 x 14 x 9 inches (including wheels and handles). That's the magic number. Buy a bag within those dimensions and you're covered on most domestic flights.

This size fits in the overhead bin on most aircraft. It's roughly equivalent to a standard 21-22 inch rolling suitcase you'd find at any luggage store.

Carry-On Size Limits by Airline

Here's what each major US airline allows for overhead bin carry-on bags:

Full-Service Airlines

• American Airlines - 22 x 14 x 9 inches
• Delta Air Lines - 22 x 14 x 9 inches
• United Airlines - 22 x 14 x 9 inches
• Alaska Airlines - 22 x 14 x 9 inches
• JetBlue - 22 x 14 x 9 inches
• Hawaiian Airlines - 22 x 14 x 9 inches

Southwest Airlines

• Carry-on bag - 24 x 16 x 10 inches

Southwest is more generous. Their dimensions accommodate slightly larger bags, which is nice if you're trying to pack everything in a carry-on.

Budget Airlines

• Spirit Airlines - 22 x 18 x 10 inches (paid carry-on); free personal item is 18 x 14 x 8 inches
• Frontier Airlines - 24 x 16 x 10 inches and 35 lbs (paid carry-on); free personal item is 18 x 14 x 8 inches

This is where things get tricky. On Spirit and Frontier, you only get a personal item for free. That's the small bag that goes under the seat in front of you. If you want to bring a full-size carry-on into the overhead bin, you'll pay an extra fee, often $35-$65 depending on when you buy it.

Personal Item vs. Carry-On: Know the Difference

Every airline lets you bring two bags into the cabin: a carry-on (overhead bin) and a personal item (under the seat). They're not the same thing.

• Carry-on - Goes in the overhead bin. Rolling suitcases, duffel bags, garment bags.
• Personal item - Goes under the seat in front of you. Backpacks, purses, laptop bags, small totes.

Most airlines limit personal items to roughly 18 x 14 x 8 inches, though some are more relaxed about enforcement than others. The budget carriers are the strictest here.

Weight Limits

Most US domestic airlines don't enforce carry-on weight limits. You won't get weighed at the gate on American, Delta, or United. But there are exceptions:

• Frontier enforces a 35-pound limit on carry-ons
• International airlines frequently impose weight limits of 15-22 pounds

Even without official weight limits, your bag still needs to fit in the overhead bin. If it's so stuffed that it doesn't close, you'll get gate-checked.

Airlines Are Getting Stricter About Enforcement

Here's the trend you need to know: airlines are cracking down. Many airports now have automated bag sizers at the gate that scan your luggage dimensions electronically. There's no negotiating with a machine.

A few things that trigger gate-check enforcement:

• Overstuffed bags that bulge past their frame dimensions
• Backpacks packed so full they exceed personal item sizers
• Full flights where overhead space runs out quickly
• Budget airlines where gate agents actively check bag sizes

If your bag doesn't fit in the sizer, you're checking it. On budget carriers, that means paying the checked bag fee at the gate, which is always more expensive than buying it online.

How to Pick a Carry-On That Works Everywhere

The safest bet is a bag that fits within 22 x 14 x 9 inches. That covers every major US airline and most international carriers too. Here's what to look for:

• Measure including wheels and handles - Airlines count everything, so that fancy telescoping handle is part of the height
• Hard-shell vs. soft-sided - Hard-shell bags have fixed dimensions and won't pass if they're too big. Soft-sided bags can compress slightly but also expand when overpacked
• Look for "carry-on size" labels - Most luggage brands clearly label which bags meet airline carry-on standards
• 21-inch bags are the sweet spot - They're marketed as carry-on size and typically measure 21-22 inches including wheels

What Happens If Your Bag Is Too Big?

If your carry-on exceeds the size limit, the airline will gate-check it. This means it goes under the plane with checked luggage, and you pick it up at baggage claim.

On full-service airlines, gate-checking is usually free. On budget carriers, you'll pay the gate-check fee, which is typically the highest baggage fee the airline charges. Spirit, for example, charges significantly more for gate-checked bags than for bags purchased online during booking.

Pro tip: if you're on a full flight and your bag is within size limits, you might still be asked to voluntarily gate-check. This is free and often announced over the PA system. If you don't have fragile items or essentials you need during the flight, it's no big deal.

Regional Jets: The Exception

Even if your bag meets the airline's carry-on size, you might need to gate-check it on regional jets. These smaller aircraft (like the CRJ-200 or ERJ-145) have tiny overhead bins that can't fit standard carry-ons.

This is free. You leave your bag at the jet bridge door and pick it up at the same spot when you land. Just remove anything you need during the flight first.

International Airlines: Different Rules

Flying internationally? Size limits can shrink. Many European and Asian carriers cap carry-ons at 21.5 x 13.5 x 7.5 inches and enforce weight limits of 15-18 pounds. Always check your specific airline's policy before packing.

If you're connecting between a US domestic flight and an international carrier, your bag needs to meet the stricter of the two size limits.