I consider switching to a soft suitcase. The size should be less than 158cm aggregately which I believe most airlines stipulate as the maximum size for free entrustment, but some soft suitcases, especially expensive ones like Samsonite, can usually be beyond the limit in a few cm or more.

This is especially true in suitcases that have redundant pockets on the front, which is openable without unlocking. They may also have expanders. And since the soft suitcase has more flexibility to pack into, the total size can expand more, depending on your contents. So the aggregated size can sometimes become 163 or even 168 or more, I think.

In these cases, do airlines care about these expanded size? Do they calculate the size of the baggage by the original size or by the actual, packed size?


Sorry if I failed to explain it well. The "original size" is not based on what a manufacture stipulates (which I just found written on the original post, sorry) but based on a straight line on the bag. This line would become a curve after the overloaded contents swell it up, which I meant as a "actual size". If the airline staff measures the baggage based on the edge of the baggage, it would be close to a perfect straight line and is considered an "original size".

  • 1
    Depends on the agent. I have seen rhem measure suitcases.
    – user13044
    May 30, 2017 at 12:23
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    The cheaper the airline, the more it will be measured. For the purpose of flight, pack your suitcase as tight as possible, preventing any extra redundant pocket usage.
    – user45851
    May 30, 2017 at 12:34
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    Actual, packed size seems much more likely. To implement original size the airline would need a database of sizes of all makes and models of suitcases, covering all manufacturers in the world. Even given that, they would need to determine the make and model of the specific suitcase. To implement actual size they just need a tape measure and the suitcase. They already have the suitcase, and tape measures are cheap. May 30, 2017 at 13:40
  • Can I know in advance which airline is more generous?
    – Blaszard
    May 30, 2017 at 15:08
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    No airline cares about the theoretical size of your bag, they only care about the actual size. If they care at all that is.
    – Berwyn
    May 30, 2017 at 19:28

2 Answers 2


Yes. Airlines have size limits that apply to the actual luggage carried by the passenger; airlines do not care what the stated or official or nominal dimensions are. As you say, soft sided luggage can be stuffed to be large, any luggage with external pockets can be stuffed, and stated/official sizes often do not include wheels, straps, handles, etc.

In most cases, airlines do not ever actually measure luggage carried or checked by a passenger. They usually have a rigid (often metal) sizer in the check-in area, at the boarding gate, and sometimes elsewhere. Airlines sometimes do not enforce their size limits. When they are enforcing them, an agent will instruct a passenger to place his or her bags, one at a time, into the sizer. If the bag fits, it's approved. If it has to be shoved in, or won't fit, it's rejected.

The situation varies by airline, by airport, and sometimes by agent. For example, in the U.S., each airline sets their own rules for carry-on bag sizes, but the FAA requires airlines to enforce whatever rules they have set. If an FAA inspector observes an airline not enforcing its rules, the airline can be penalized.

Airlines generally have weight limits as well.

Here's an example of an airline luggage sizer (for United Airlines):

United luggage sizer

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    This type of sizer only works if there is a separate upper limit for each dimension, commonly the case for carry-on bags. A different system has to be used for checked bags that are subject to a sum-of-the-dimensions limit. I would still expect it to be based on the actual size, because that is what matters to the airline. Jun 1, 2017 at 0:36
  • For sure airlines only care about actual size of the bag as presented to them. As I mentioned, stated/official sizes are meaningless, since, besides the fact that suitcases can bulge due to being stuffed, the stated size often exclude handles, wheels, straps, etc.
    – jetset
    Jun 1, 2017 at 1:19

Airlines only care about the volume of your bag: they have a total amount of volume available to store passenger stuff and what matters primary to them is the real, actual volume of your bag. Sides maximum lengths are used "just" to avoid to have to play Tetris with bags and to lose precious available volume 'cause of weird shapes.

So it's not a matter of measuring edges, nominal sizes, and other strange things like that: your bag must fit into a specific maximum volume, defined by a set of maximum sizes technically called a "bounding box".

At check-in, if the officials think your bag is to big, they just measure it against this virtual or physical box: if it fits is ok, otherwise it's not. If the maximum size is i.e. 50cm, and your bag is 48cm with a 10cm side pocket coming out of it, it simply doesn't fit in the bounding box and the bag is not ok.

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