How luggage is measured: A traveler’s guide to bag sizes and airline rules

Trying to figure out if your suitcase is too big for the overhead bin, or too heavy for a checked bag? I’ve been there, too. 

Knowing how luggage is measured isn’t always straightforward, and airlines don’t exactly make it easy. Between varying size limits and confusing policies, it’s no wonder travelers get caught off guard with surprise baggage fees. 

Here’s what you need to know about how airlines measure luggage before your next trip.

Why knowing how luggage is measured matters

Oversized or overweight bags often come with surprise fees that can range from $50 to $200. Plus, if your carry-on doesn’t fit in the overhead bin, it might be gate-checked, and you could be forced to part with valuable items like electronics or medication.

How do airlines measure luggage? 

Airlines typically measure luggage using linear dimensions, which means the total sum of your bag’s height, width, and depth. For example, if your suitcase is 22 inches tall, 14 inches wide, and nine inches deep, that adds up to 45 linear inches.

This number matters because most airlines have strict limits. For checked bags, the maximum is often 62 linear inches. For carry-ons, it’s usually around 45 linear inches. Keep in mind, these measurements include wheels, handles, zippers, and any protruding parts, not just the main compartment.

Are luggage dimensions measured packed or empty?

Most luggage manufacturers list the dimensions of bags when they’re empty, and that’s usually the size you’ll see when shopping online or in stores. However, airlines may assess your luggage when it’s packed. And if it’s bulging or overstuffed, it might not fit the airline’s sizing requirements.

It’s smart to measure after packing your bag to be sure it still falls within the limits, especially if you’re flying with a low-cost or international airline, which tend to be stricter.

Carry-on size vs. personal item size: What’s the difference?

If you’re trying to figure out whether your backpack counts as a carry-on or a personal item, you’re not alone. Airline pilot almostcaptainmorgan says the difference really comes down to size and where the bag fits. Carry-ons are slightly larger and meant to go in the overhead bin, while personal items should be small enough to fit under the seat in front of you.

Here’s a quick breakdown:

• Carry-on luggage is usually limited to 22 x 14 x 9 inches, including wheels and handles.
• Personal items (like a purse, laptop bag, or small backpack) need to be small enough to fit under the seat in front of you, often limited to 18 x 14 x 8 inches or smaller.

But you should always check the airline’s policy before you fly. Some budget carriers have much tighter restrictions, especially for basic economy tickets.

How to measure your luggage at home

Want to avoid those last-minute gate checks or overweight fees? Here’s how to measure your luggage yourself:

1. Use a soft measuring tape or a ruler to measure from the bottom of the wheels to the top of the handle (for height), and then side to side and front to back.
2. Add those three numbers together to get the total linear dimensions.
3. Weigh the packed bag using a luggage scale, especially for checked baggage.

It’s a good habit to double-check your suitcase size before every trip, especially if you’re flying a new airline.