Measure length, width, and depth with a tape measure or ruler

To measure luggage, you need the three dimensions: length (the longest side from top to bottom), width (side to side), and depth (front to back). Use a soft measuring tape or a rigid ruler, and measure the outer shell of the bag, not the interior. Place the tape flat against each side and note where it starts and stops. Write down all three numbers in inches or centimeters — whichever your airline or venue requires.

The order matters for how you report it. Most airlines and baggage handlers list dimensions as length × width × depth. If your bag is 22 inches tall, 14 inches wide, and 9 inches deep, you would say it is 22 × 14 × 9. Keep these numbers handy; you will need them to check size restrictions before you travel.

Key Takeaways

  • Measure the outer shell of your luggage in three directions: length (top to bottom), width (side to side), and depth (front to back).
  • Add all three dimensions together to get the total linear inches, which is how most airlines enforce carry-on and checked baggage limits.
  • Measure with the bag standing upright and empty, with wheels and handles in their normal position.
  • Different airlines have different size rules, so check your carrier's website before you pack to avoid fees or gate-checking.

Add the three dimensions to find linear inches

Once you have length, width, and depth, add them together. This total is called linear inches (or linear centimeters if you measured in metric). Airlines use this number to enforce baggage size limits. A carry-on bag that is 22 × 14 × 9 inches totals 45 linear inches. Most U.S. airlines allow carry-on bags up to 45 linear inches; checked bags usually max out at 62 linear inches.

Linear inches matter because a bag can be small in one direction but large overall. A long, thin duffel and a compact cube might have the same linear total but look completely different. The airline cares about the total because that is what determines whether the bag fits in the overhead bin or under the seat in front of you.

Measure with the bag empty and standing upright

Always measure when the bag is empty and in its normal standing position. If you measure a soft-sided bag while it is packed, the dimensions will be larger and will not match what the airline expects. Wheels should be in their normal down position, and handles should be extended or folded as they normally sit — do not flatten or compress anything artificial.

For rolling luggage, measure from the bottom of the wheels to the top of the bag. For duffels or soft bags, lay them flat on a table and measure from end to end. The goal is to capture the space the bag actually takes up when you are traveling with it, not some compressed version that exists only in your hands.

Check your airline's specific size rules before you book

Carry-on and checked baggage limits vary by airline and sometimes by ticket type. Southwest, Delta, United, and American all have different rules. Some airlines allow one free carry-on and one personal item; others charge for a second bag. Budget carriers like Frontier and Spirit often charge for any checked bag and have tighter carry-on limits. Low-cost international carriers may have even stricter rules.

Visit your airline's website and search for "baggage size" or "baggage dimensions." Write down the exact limits for both carry-on and checked bags. If you are flying with a budget carrier or an international airline, also check whether soft-sided bags are treated differently from hard-sided ones, and whether wheels and handles count toward the total. Some airlines measure only the bag itself; others include handles and wheels in the dimension.

Understand the difference between carry-on and checked baggage limits

Carry-on bags must fit in the overhead bin or under the seat in front of you. Most U.S. airlines cap carry-on at 22 × 14 × 9 inches (45 linear inches), though some allow slightly larger bags. Checked bags have more room but are subject to weight limits, usually 50 pounds for domestic flights and sometimes less for international ones. A bag can be within the size limit but still rejected if it weighs too much.

If your bag is too large for carry-on, you will have to check it, which costs money on some airlines and may delay your arrival if the bag does not make it on your flight. If your checked bag exceeds the airline's size limit, you may face an oversized baggage fee, which can range from $50 to $200 depending on the carrier. Measuring before you travel prevents these surprises.

Measure soft-sided bags carefully because they compress

Soft-sided luggage is trickier to measure than hard-sided because the fabric can compress or expand slightly depending on how full it is and how it is positioned. Measure the bag when it is empty and sitting on a flat surface, with all pockets zipped and no pressure applied. If the bag has a frame or structure, measure around it in its normal state.

Some soft bags have expandable sections that add an inch or two when fully opened. If your bag has this feature, measure it both ways — with the expander closed and with it open — so you know the maximum size. If the expanded size pushes you over the airline's limit, keep the expander closed when you travel, or use a checked bag instead.

Use a luggage scale to check weight at the same time

While you are measuring dimensions, also weigh your packed bag. A luggage scale is a small digital scale that hangs from your bag's handle and costs $10 to $25. Weigh the bag when it is fully packed so you know whether it will pass the airline's weight limit. Checked bags usually max out at 50 pounds; some airlines charge $25 to $50 per pound over that.

Knowing both the dimensions and the weight before you leave home means you can repack or remove items if needed, rather than discovering the problem at the airport. Many travelers measure dimensions but forget to check weight, then face a surprise fee at check-in.

Frequently Asked Questions

Do wheels and handles count toward the luggage dimensions?

It depends on the airline. Most major U.S. carriers measure the bag itself and do not count wheels or handles. However, some international and budget airlines do include them. Check your specific airline's policy on their website before you measure. If they do count wheels and handles, measure from the very bottom of the wheels to the top of the extended handle.

What if my soft-sided bag is slightly over the size limit when packed?

Soft-sided bags have some leeway because they compress. If your empty bag measures within the limit, you will likely be fine even if it bulges slightly when packed. However, if the empty bag already exceeds the limit, it will almost certainly be rejected or charged as oversized. Measure when empty to know your true maximum.

Can I measure my luggage in centimeters instead of inches?

Yes. Most airlines publish size limits in both inches and centimeters. Measure in whichever unit you prefer, but convert to the unit your airline uses before you compare. One inch equals 2.54 centimeters. If you are flying internationally, centimeters may be easier since most non-U.S. airlines use metric measurements.

Do I need to measure my personal item or just my carry-on?

Most airlines allow a personal item (purse, backpack, laptop bag) in addition to a carry-on bag, and personal items usually have looser size limits. However, it is worth measuring both if you plan to bring two bags, because some airlines are strict about what counts as a personal item. A bag larger than about 18 × 14 × 8 inches may be considered a carry-on instead.

What should I do if my luggage is too large for the airline's limit?

If your carry-on is too large, check it instead and bring a smaller personal item on board. If your checked bag is too large, you have three options: use a smaller bag, remove items and mail them separately, or pay the oversized baggage fee if the airline offers one. Measuring before you pack gives you time to choose the best option.