Domestic carry on versus international carry on

I'd recommend a wheeled international size, as you can fly either way with it. Just make sure measurements published are the true measurements of the bag. Why buy a bag that you can only use domestically?

The International size are a bit smaller, so they would work for domestic, too. However, different airlines have different size/weight rules, so no guarantee that any bag you choose will be allowed by every airline.

One asks a simple question and opens up a can of worms. Here is a list of the size and weight allowance of 170 airlines. It is more airline dependent, not whether domestic or international....unless you mean the small domestic planes where 'allowed' luggage sizes don't fit.
https://travel-made-simple.com/carry-on-size-chart/
I suggest looking at airlines that you are more likely to use and try to find a size that would fit all or most.

Oi. There is the wheels/no wheels debate, too. Given the same external dimensions, the frame and transmission on a wheelie consume valuable internal volume.

Choose wisely, grasshopper.

And then there's the weight issue. Anecdotal evidence suggests that at least some international discount airlines are weighing carry-ons at the gate. So a more or less definitive answer might be to buy the smallest, lightest carry-on that will meet most of your needs. If you mostly travel domestically and usually check a bag internationally then you could buy one of the larger domestic-sized carry-ons. If you plan on regular international travel and want to do carry-on then you should get a smaller international-sized bag. And if you are planning to regularly fly internationally on a discount airline then you may want a smaller and lighter carry-on.

@Maria, thank you for the link to the comparative chart, although it should be called "Travel-made-TOO-simple" or possibly "metric- conversion-for-the-math-challenged". If you click on the specific limits for Air France, KLM, and Lufthansa internationally, you will see that they all have a max height limit of 55cm, but the website converts them as 21.5" for Lufthansa and KLM, and 21.7" for Air France. The actual height limit is 21.65" for all three airlines.

Also, LIZ (and kclyons), it is the US domestic size limits that are smaller. American, Delta, and United all have the same limit, 22x14x9 inches, or 2772 ci. According to Maria's chart, Air France and KLM at 2935 ci, Lufthansa @ 3087 ci, and British Air @ 3845 ci all have larger size limits. But sometimes individual int'l dimension limits (L, W, or H) can be less than US allowances. For instance, all but BA limit the height to 55cm or 21.65 inches, which is a little less than the US standard, 22 inches. So even if the bags include the wheels and handle, which many manufacturers ignore, a US regulation bag would be a little too high for European airline standards. It should also be noted that KLM and Air France limit the width to less than the American standard of 14 inches.

The reason these smaller International single dimension limits are important is that rolling bags tend to be rigid and rigid American regulation sized bags cannot be deformed to fit European sizers. That is why I would recommend that if you can possibly carry your bag on your back (AF & KLM, 26#; Lufthansa 17.6#) get a soft-sided convertible bag since it's flexibility will allow it, if not fully packed, to conform to sizers with smaller limits.

@Lee, I learned that Air Canada also rounds down to the nearest 1/2 inch so its 55cm is 21.5. Given that inches are broken down into eighths and 16ths, how do you get 21.7 on a measuring tape ;-)?
You are correct that something mushy and sans wheels works best for fitting more airline luggage testers, but for some, wheels are vital for comfort and ability to transport.
Heck the easiest and lightest but lest useful would be a black Hefty bag duct taped to the airline's size configuration.

"The sizes are different for international versus domestic." - I would challenge that statement. The limits are specified by the airlines, and are different for different airlines. In Europe at least they do not vary for domestic and international flights, it is all the same.
You need to look up sizes on the airline websites.

For example, Easyjet is relatively lax, 50 x 40 x 20 cm.
Ryanair is smaller, 40cm x 20cm x 25cm.
BA is even bigger, 56cm x 45cm x 25cm.
See here for a list: https://www.edreams.com/blog/luggage-restrictions-by-airline/

...how do you get 21.7 on a measuring tape....

21 and 7/16 inches = 21.6875"is close enough to 21.7" The real concern is "sizing frame" are go or no-go and did the airline use an English measure tape or a Metric tape? Do you feel lucky?

The carry on sizes vary typically by aircraft, not necessarily by destination. The carry on dimensions for a CRJ 900 will certainly be different from those of an Airbus 330-300 or 767-400.

But seven tenths is way bigger than 7/16!

All European airlines use cm, like the examples I quoted. You need to get a cm tape!
The only country in the world that uses inches is the USA.
In reality most airlines use a sizing box, it either fits or it doesn't. That is the advantage of a squashable soft case.

Click here for a photo of an easyjet one. This is before check-in, so you can check your own bag before handing it in.

Sorry 11/16 = .6875.

Edgar,
Thank you for the precision math clarification.
Oh my! Just get a 40 liter bag and call it quits. 20" x 14" x 9"
If you are going to Asia - you need to check Asian requirements.
African Safari? Get a 40 liter duffle bag (eagle creek migrate or Red Oxx lil' hombre).

21-11/16 = 21.6875

but 55 cm = 55/2.54 = 21.5354, and
21-5/8" = 21.625

21-5/8" (21.625") is closer (0.02854") to 55 cm (21.5354 then 21-11/16 (21.6875) is to 21.5354 (.03396), and 21-5/8" is not over the limit, so use 21-5/8. Or if you want to be really precise, and you have a scale graduated in 32nds of an inch, use 21-21/32 (21.65625) inch. Then you are off by only 2 thousandths.

Yes, Sun-Baked, just get a soft US regulation bag at 22x14x9, without wheels or handle, don't pack it to bulging, and call it quits.

My two (or is it three?) favorite bags,
Bihn Aeronaut 30: 19.7" (w) x 12.6" (h) x 7.9" (d) / 500 (w) x 320 (h) x 200 (d) mm
Bihn Aeronaut 45: 21.9" (w) x 14" (h) x 9.1" (d) / 555 (w) x 355 (h) x 230 (d) mm
and Patagonia MLC: 22.75 x 18 x 6.75 inches

1/8th vs 1/16th vs 1/32th accuracy. If it's a soft sided case is will be close enough and could fit in a sizing frame with a firm push. If it's a hard frame case, good luck in getting it out if you push too hard to make an almost close enough case fit. Soft sided cases can fit if you don't over stuff them. If you go with the hard shell or rigid frame wheelie, you want to be on the minus side of the maximum dimensions.

These responses are way overthought. Most bags will never fit every plane...but, oh my, a bag can be checked! In the meantime, most internationals will fit a 21.5 x 14 x 9 inch bag, which is a lot of bag choices. Or if there is tremendous fear, go for an underseat bag at 18", but then you are fine tuning quite a bit. You can carry a soft bag on your back if you want, but in the majority of instances a mostly soft wheelie like EC, ebags or Rick Steves works fine in the international measurement box. It is not a bad idea to check your usual carriers, but some might allow you more than you need. If weight starts being an issue and you don't want to pack that light, just check. I have no problem carrying or checking my RS wheelie via small jet (gate check) or usual transatlantic. Hold harmless, domestically I tend to use my 16" wheelie, which I love, but wouldn't want to limit myself like that overseas...someday I might shop.

Well, while not technically correct, I look at my use of airlines. Living in the US, I am always flying a US airline, almost always Delta, or one of a partner carrier under codeshare. In that case, size is of less concern, US carriers are fairly liberal, as long as you don't over do it, you will be fine. For flights within Europe, there is a concern, but for a three week trip, I find weight more of an issue, figure in Budget airlines, more of an issue. In that case, since flights are usually direct, checking a bag is the best option and eliminates most worries.

I guess it's a matter of personal philosophy.

Some people seem to be determined to take absolutely everything they can (or hopefully even more), given the airline restrictions, and what they can push, pull, or drag through airports, down streets, up narrow stairways and onto buses and trains. Me? I love the freedom of having an 11 or 12 pound bag I can handle easily. I love it so much that I would rather spend a few minutes each night, while I writ in my journal, sort my pictures, or figure my expenses, washing out a couple items I wore that day, than lugging three weeks worth of clothing around for the entire trip.

Some people seem to be determined to take absolutely everything they
can (or hopefully even more), given the airline restrictions, and what
they can push, pull, or drag through airports, down streets, up narrow
stairways and onto buses and trains. Me? I love the freedom of having
an 11 or 12 pound bag I can handle easily.

I think we've all shared aircraft space with the "bring-everything' people. And, Lee, I admire your minimalist travel philosophy. However, there are a lot of people who when packing for a trip, fall between your philosophy of "a 12 pound pack for three weeks" and the devotees of "I need a new outfit for every day plus accessories and shoes."

When you're in the middle of that packing-philosophy continuum, you get into these discussions as you seek to balance traveling light (if not extremely light) with bringing what you need to function and enjoy your travels.

I doubt that anyone who's bothered to find this discussion forum and sign up to participate, seriously intends to "lug three weeks worth of clothing around for an entire trip," as you characterize it. In fact, the original question has to do with finding a bag that will meet the airlines' ever-shrinking requirements for carry-on bags. None of which would allow you that mythical three weeks' worth of clothing changes. (Well, okay, maybe 21 thong bikinis would fit in, and more power to anyone who's booked three weeks in some paradise where that's the necessary wardrobe!) Heck, I don't even own enough clothes to get through three weeks without doing laundry, when I'm at home.

So, here we are in the middle. Some of us (that includes me) can't do backpacks. In my case it's some spinal issues that mean using anything larger than a small daypack = pain and suffering. I wish it weren't that way. Some of us have to bring along medical devices (canes, CPAPs, braces) that we may not use when you see us at the airport but will be necessary during the trip. (I often pack a folded cane in case a tricky joint acts up while I'm away.)

Also, on my personal list of necessities: camera gear. I would absolutely not enjoy my trip to interesting places if I couldn't take photos, and I'm way beyond the snap-it-with-your phone level. I do not haul a huge camera and lens assortment overseas, but there will be some such gear in my bags.

I think I'm like pretty much everyone on this forum, in that I expect to - and do - handle my luggage when on the ground. Yes, it's a roller bag, and yes, I easily handle it both by rolling and by picking it up and carrying it when required. My bag rolls nicely behind me, and I have no problem keeping it from tipping over while in motion. I tend to check roller bags that are "just over carry-on size" to use a phrase I found on this forum. I've easily traveled with my roller bag + little duffel or shoulder bag: through airports, down streets, up narrow stairways, and onto buses and trains.

And, back to the topic: I agree, the best bet to figure out a future-proof bag to meet carry-on requirements, is to focus on the airlines you are most likely to fly and don't worry about the rest. I'll fly Spirit or Easyjet when hell freezes over, so I don't worry about them. I fly Southwest domestically as often as possible and BA overseas almost exclusively. Their carry-on requirements are relatively generous including weight limits. I can live easily within them. Also, I have been known to drive out to our airport, pay to park for a few minutes, and take empty bags inside to try them in airline sizer boxes. That won't work if you're connecting to a flight on an airline that doesn't serve your local airport, but it's a definite way to resolve uncertainty about your bag size vs the airline's limits.

Check out Eagle Creek Expanse carry on luggage. Don't exceed 45 liters. Eaglecreek.com. There are several options for backpack convertible style, simple 2 wheel roller, 4 wheel roller, etc.. Decide what you want and get it.

In fact, the original question has to do with finding a bag that will meet the airlines' ever-shrinking requirements for carry-on bags. None of which would allow you that mythical three weeks' worth of clothing changes. (Well, okay, maybe 21 thong bikinis would fit in, and more power to anyone who's booked three weeks in some paradise where that's the necessary wardrobe!)

I’m going to rebut this statement. I’ve carried 5-1/2 weeks of clothing in a carry on. That included gear for mountaineering and also a cruise. I had a 7kg weight limit It’s all about the layers and shifting weight into a small personal item.
I’ve also traveled with just a personal item. I had more outfits than I needed. I’ve only done 1-1/2 weeks with the personal item (so far).

Three weeks is 21 days. You can get that many outfits out of two pants, a skirt, and seven tops. That’s without toppers (jacket, cardigan). I don’t know about you, but I rewear stuff within a 3 week period so I could get along with less clothing and a little laundry.

I do agree that some can’t make that size or weight requirement for medical reasons. A CPAP is large. Medication take up space. But I’ve also found that by packing efficiently I only take up half the space in a rolling carry on. I had to do that for work when I was lugging around notebooks and test proceedures.

It’s not as cut and dried as you think.

Of course I didn't mean that you can't pack for a three week trip using a carry on bag. I was responding to a comment that referred to "three weeks worth of clothes" in a manner that implied a change of clothes for every day. Instead of bringing a bare minimum that involved doing a hand wash every night. I was pointing out that nobody who would bring 21 outfits would be expecting to put them in a carry on. Obviously I didn't express that well. Sorry.

@Suz, I understood you clearly. No need to apologize IMHO.

Thanks for all the helpful suggestions. I think the garbage bag and duct tape might be the easiest. Especially if I can figure out a way to tape on wheels and a handle.

I see the packing police and the ultralight evangelists have been around.

Every airline has their own set of rules. It is very difficult for the average carry on only traveler to adhere to all. (Note I said the "average" carry on traveler.)

My bag adheres to many of the European carrier's size and weight limits for carry-ons and I try to fly those airlines.

A couple of times the big bad airlines have forced me to check my main bag. Here is what I found out:

1) My trip was not ruined because I had to check the bag;

2) I did not consider my life over;

3) The polar ice caps did not melt faster.

Yes, I did have to wait a few extra minutes for my bag but it wasn't life threatening.

Seriously, to buy a bag to fit European standards you have to start thinking in metric. Most European airlines will allow a bag that is 55 x 35 x 20/23 cm. ( The U.S. standard of 22 x 14 x 9 inches is 56 x 36 x 23 cm.) Unfortunately, the selection of European sized bags is limited in the US. More US travelers do so domestically and want the largest allowable carry on possible.

I see the packing police and the ultralight evangelists have been around.

Can we please stop with the passive aggressive snarky comments? Every time someone makes a post on packing light these comments pop out. It’s become old.

A discussion on weight and packing light will always be appropriate as long as airlines have weight restrictions on carry on bags!

If you don’t want to pack lighter, fine! But please don’t try to stop others from discussing it.

Ha! Are you sorry you asked this question?

Glad to see you kept your humor per your garbage bag/duct tape response!

La Smith

I'm drawing up a garbage bag prototype for you with wheels and a tape measure looped handle (so that it is easy to remeasure periodically) but there will be some delays in production due to the long holiday weekend

There are YouTube DIYs of adding wheels to duffle bags and backpacks for inspiration. The easiest might ge the old type of strap-on luggage wheels....like a portable foldable dolly. Would be easy to use on its own, but you want to duct tape it to the garbage bag parcel so it becomes one instead of two items.....unless it is compliant in size and weight for your personal item.

If you buy a bag that is 22 x 14 x 9, which is only a cm too large on each side by European standards do international airlines really make that big a deal of carrying it on or do they let it go?

Certainly you can check a bag. But if your flight is delayed and you want to take a different flight or (when in the US) drive to a destination, as happened to my husband and 4 of his employees this week, that checked bag will be a problem. And there are times when the airlines don't put your bags on your plane.

I have had great success with the Rick Steve's European sized expandable roller bag at 21 inches. The interior is roomy and I have stuffed in 4 packing cubes. I just did a trial pack for a two week trip to Italy and it is just under 9 pounds even with the travel towel for the beach. I have traveled with it domestically too. The good news is that I can actually lift it over my head to put it in the overhead bin. I like the outer pouch where you can store a light weight jacket with easy access to it so you don't have to rifle through the whole bag.

If you buy a bag that is 22 x 14 x 9, which is only a cm too large on each side by European standards do international airlines really make that big a deal of carrying it on or do they let it go?

Airlines have sizing boxes they use to see if the bag fits their requirements. How exact the boxes are is a point of discussion. Remember, the ailrines make a fortune charging for oversize bags. And that includes carry ons.