Am I stupid?

My carryon is 21" x 15" x 9. Which =2,835 ci. = 46,457 cm. Airline says 158 cm for carryon. What am I missing here?

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Am I stupid?

My carryon is 21" x 15" x 9. Which =2,835 ci. = 46,457 cm. Airline says 158 cm for carryon. What am I missing here?

Are you measuring the wheels too?

21+15+9=45 inches which is about 114.3 cm. So it appears you are below the limit.

Does the airline also have a weight limit for the carryon?

You aren't asked for the volume. You are asked for the SUM of the height, width , and length. 21+15+9 or in cm: 53.34+38.1+22.86=114.3

Looks like your question has been answered. Happy travels!

Then why do the airlines use multiplication signs instead of plus signs?????

Mary and CJean, thank you so much I was almost crying. My calculator was doing cubics. Good god!

It's my 1st time traveling to Europe in decades, and my other trips were music tours and my mother, all of which was organized for me. This is one steep learning curve.

The symbol "x" is used for many things. While mostly known for multiplication it is also used to minimize the concept of "by" such as the measurements of 21 x 15 x 9 would be read as 21 by 15 by 9. Since length is measured by addition and not multiplication it's a given that the X means "by."

Then why do the airlines use multiplication signs instead of plus signs?????

They are using the "x" in the manner that lumber is described, i.e 2x4 becomes 2* **by** 4" , (not 2 *times* 4)

We always take a 21 inch ultra light swivel wheel carry on bag. And we have no problems with the legacy airlines. The bags fit in either Airbus or Boeing overhead compartments.

And we limit ourselves to 22 lbs/10 kg. in case the bags get weighed.

No problems.

Dreams Come True, (great user name!!! )

I say this to kids and adults alike:

you are NOT stupid

(or whatever other harsh self descriptors a kid might use like ugly or fat)

🤪🙃 how about " I'm confused " or "this does not make sense to me"

😅 sorry that you accidentally triggered my teacher voice😁

And know that there are lots of people here who will patiently help you figure out the most weird and confusing travel questions

doric8 THANK YOU! I am doing everything from scratch, and it is overwhelming. Who knew that X meant BY in different scenarios?

Make sure you don't just take the manufacturer's dimensions. Sometimes, the actual measurements are different. It happened to me when I took a European flight. My carry-on was bigger than stated and did not fit into the sizer. So, I had to gate check it with a payment.

Airline says 158 cm for carryon

What airline says 158 cm for carryon????

I checked 8 trans-Atlantic airlines, Lufthansa, Air France, British Air, United, American, and Delta, KLM, and SAS. Except for British Air at 208 cm, the other seven all specify 158 cm for **Checked** baggage.

For 5 out of 8, the ** carry-on** limit was 114 or 115 cm. Lufthansa and SAS was 118 cm and British Air was 126 cm for carry-on. None of the airlines I checked showed 158 cm for carry-on baggage.

It’s called linear inches or centimeters. Different way of measuring. Airline is interested in external dimensions for cargo space reasons. We all need to learn new things. I was confused by airline linear dimensions as well, until I learned what it meant.

Actually, most airlines do not express the limit in linear cm or inches, but as maximums for the length, width, and height of a bag. For US airlines United, American, and Delta that is 22 x 14 x 9 inches, so your 15 inch width is over and your bag might not fit in a sizer if one is used.

United, for instance, does not say the maximum linear dimension of a checked bag is 158cm or for a carry-on is 114cm; I just got those dimension by adding up the three maximum dimensions, 76 x 52 x 30 cm (=158cm or 62 in.) for checked bags and 56 x 35 x 23 cm (= 114cm or 45 in.) for carry-on bags that they do show on their website.

If you go just by the linear inches, a 15 inch on-a-side cube, would satisfy the 45 linear inch limit for checked bags, and a 15 inch cube would have 3375 cu. in. capacity, 22% more than the 2772 cu. in. which you get from the three maximum side dimensions, 22 x 14 x 9 inch, which United does specify. If everyone had a 15 inch cube "bag", the overhead bins would not fill very efficiently. On the other hand, a 21 inch cube checked bag in the hold would probably not be a problem.