My name is stacey and i am 18 years old and i am traveling to europe next spring. I am going to take a backpack for my carry on but i am not sure how many liters it should be and also what kind of brand i should get.

For most major carriers, max carry-on size is 41 linear inches (22x14x9)-- not sure of the cubic liter measurement, but I'm sure you can find that online. With the linear measurement, you have a little leeway of course, because a soft sided bag can be squeezed. I recommend a waist belt, they help a lot, as well as an attached rain cover. I just ordered this one: http://www.zappos.com/osprey-porter-...-green#prdInfo.
I had a kelty for years that was great.

You should go to a large sports store such as REI and get a pack that fits your body. The sales people will help you buy the correct pack.

>>max carry-on size is 41 linear inches (22x14x9)<<

That should be <B>45</B> linear inches

The size of luggage (dimensions, volume, and weight) are usually stated on airline web pages. The last time I flew the allowable dimensions for US carry-on were 22" x 14" x 9". Based on volume that would be 2,770 cubic inches (45 liters).

I suggest that you get a 22" bag on wheels instead of a back pack.

is the backpack going to be your main mode of carrying your stuff or will you have hold luggage and need a separate back back for use as a day bag during your travels?
If the day bag option I would go for a 25litre bag with a fold over flap rather than zip top style.with the fold over flap you can easily fold jackets or sweater in the flap to make carrying easier.

Mmmm. She is planning to use the backpack as a carryon, so presumably she has another bag checked. She doesn't need two rollers.

OP, a back pack as a carryon is a good idea because you can leave your main bag during the day and carry the stuff you need just for that day -- water, snacks, guidebooks, iPad, raain jacket, etc -- in the daypack.

Be really careful about leaving stuff in the outside mesh pockets. Water bottles are okay, but people put phones in them, and if I were not an honest person, it would be very easy to steal them. Similarly, don't leave the pack on a chair in a cafe or on a wall in a public place because there are people, some on bikes, who will snatch them as they go by.

Whatever luggage you use, try really hard to cut down on the amount of stuff you carry. If you need clothes, you can buy them over there if you are a normal sized person, and they make nice souvenirs. They have the pretty much the same stuff in drugstores that we do here, sometimes more and better. If you pack for every possible contingency, you will need a van to carry your stuff.

Sorry for my typo, but the individual specs are more important for fitting into an overhead compartment.
Stizzlestick, you need to clarify if you meant a pack as your primary luggage, or as a day pack.

Backpacks can be rugged, which also means heavy. For a day bag I now use a simple one-strap bag that I can wear over the shoulder. It doubles as computer carrier for my small laptop. You really don't need to lug around a big backpack for daytime activities. They are awkward in crowded spaces such as the subway; the locals don't enjoy being bumped by your trailer. If you think you need extra space for your belongings, try to travel lighter. You will find pay washing machines where you are going so you can make your wardrobe more portable.

Ackislander - why would you think she is also checking a bag? It is perfectly possible to live out of a carry-on size backpack for months at a time. I travel with one carry-on size bag, although I check it, plus a small day bag. For backpacks I recommend Eagle Creek convertibles, but make sure that the waist belt is taking most of the weight.

This sort of thing is good for both needs: http://fr.thenorthface.com/tnf-fr-en...d-luggage.html
But it is quite heavy before you have put anything in it.

As you are coming to the U.K. in Spring you will need a jacket which is warm and waterproof. If your backpack is your only bag then your jacket could almost fill it

"If your backpack is your only bag then your jacket could almost fill it". Sheesh.

1. You can always buy it when you get there.
2. You wear the jacket onto the plane/train/bus.
3. You wear layers and don't need a big jacket.

You can get wheeled backpacks with a zip-off daypack. That allows you to sightsee in a city with just the daypack, as long as you can safely store your main bag at the train station or wherever.

In addition to the size, look at the weight of the bag. Lighter is always better.

thanks guys for all of your help oi just was wondering what other individuals preferences are

The answer to what size you need lies within the website of the airline(s) you are travelling with. They all state clearly what the maximum dimensions and weight for carry-on are on their website, and whether or not you are allowed a second, personal item, or not.
Budget airlines have different allowances to the bigger airlines.