Is my Samsonite 28" suitcase too big?

[sk_]

Im flying from Raleigh to Vegas (stop in Atlanta) and from Vegas to San Francisco. I am confused with transforming inches to centimetres and Im now worrying that my suitcase is too big. I bought Samsonite 28" suitcase, which size is: 

Body Dimensions: 28" x 20" x 12.25"

Overall Dimensions: 30.5" x 21" x 12.25"

Do I need to pay extra for this bag or is this okay?

[TheMiddleSeat]

You should be fine. The maximum size, L+W+H is 62" inches.  I suspect luggage manufacturers know that's the industry standard and design their bags accordingly. Additionally, as it's an actual suitcase and not a box or other strange packaging no one will give it a second thought about being oversize. If you showed up with a box with the same dimensions it might get measured.

Have a good trip! 

[DancingDavidE]

If you have carried this suitcase on other flights, it most likely will be fine for Southwest as well. Southwest flys 737 aircraft which means the overhead bins are uniformly ample. (The front of the plane has shallower bins, but still bigger than regional jet size overhead bins.)

[TheMiddleSeat]

28" is a full size bag, I wouldn't advise carrying it on. Definitely checking that one. 

[DancingDavidE]

None of these are 28"...you'll want to prepare to check for sure, even if you do manage to carry it on as a backup:

https://www.ebags.com/buyingguides/luggage-and-travel/carry-on-luggage-size

There will be a box at the ticketing area of the airport where you can see "does it fit?" - also if you are relatively early boarding you can take up extra room putting your bag in sideways (if you make it on the plane with the luggage) although this has potential to cause someone else to gate check if all the space is taken and your item was using more than your share of the space.

I don't condone that necessarily, but it would be "no harm, no foul" if the flight wasn't packed. Every once in a while I see a flight with some leftover bin space, but not much.

[TheMiddleSeat]

I don't think OP was inquiring about carryon, but certainly all good and valid information. I hadn't seen the eBags listing with all the size information.