I'm looking into buying my first ever serious backpack for hiking/large trips. I'm unsure of how large I should go. I currently own a 35 Liter bag, which was great for weekend trips when I was studying in Europe, but I had issues trying to do 10 day trips with it. So what is a good size? 75 Liters, 65 Liters, and 55 Liters seem to be the three most common sizes above 35 Liters. However, I've read a bunch of places that 75 Liters is too large for anything but the longest trips.

My current upcoming trip that is prompting this is the Trans-Mongolian railroad. I'm not doing the entire thing all at once on the train - I plan to stop at varying places, so I don't necessarily need to bring as much with me on the train as someone else might. My guess is I'll be doing it for 4-5 weeks. I know the weather can be a bit unpredictable this time of year, so I'll have a few extra clothing items. I'm sure I'll want to buy some things as well.

Does anyone have any experience with this? Did you do the Trans-Mongolian (or any Trans-Siberian variant) and find your bag to be too small or too large?

Should I get a 75 Liter, 65 Liter or 55 Liter bag? Thanks!

  • Hi, can you kindly provide more information that makes this a less opinion-based question? In the current format, the question is likely to be closed.
    – uncovery
    Commented May 20, 2014 at 5:27
  • @uncovery Not sure that there is anything more than experience/opinion to the answer. I'm looking for someone to tell me how big of a backpack I need, and, if 75 Liters (the largest common size it seems) is too large. Commented May 20, 2014 at 5:28
  • @uncovery I just edited it to make it more specific, as best I could. Commented May 20, 2014 at 5:33
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    It's still opinion based. "Did you find it too small or too large?" - you could get a "too small" answer and a "too large" answer, and then which one would you accept?
    – Mark Mayo
    Commented May 20, 2014 at 5:36
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    I feel it could still ask the same question but with a reword. "Will a 55 litre bag be big enough" for example, although you could still argue yes for just about any size. I did that trip 3 years ago and took a 75L, while my friend had 4 tshirts and some trousers for 4 months. It's subjective :/ I may still try to answer in a bit when I've got a chance, hopefully the answer can turn it around a bit.
    – Mark Mayo
    Commented May 20, 2014 at 5:48

3 Answers 3


Right, so after thinking about how I'd answer this...

Why packing is an individual thing

Each to their own. Some friends backpacked South America and New Zealand with day packs. Others take extra luggage and suitcases. It all depends on what you think you'll need. Odds are you'll overestimate - you never need everything. It's easier to pack less, and buy on the way as you go if you decide you really, really need something.

My packing for Mongolia

I did a trip from London to Mongolia over 4 months on public transport in 2011. I took a 75L pack on my back, and a small daypack on my front. The main reason is my electronics and my medicine - about a third of my pack was medicine.

Means of travel

In terms of how I travelled, it was a mix of public transport - shared taxis, buses, trains, hitchhiking. In Russia and Mongolia, I (mostly) took trains, including parts of the trans-Siberian route and the trans-Mongolian - well, up to Ulan Bator. I'd love to have continued, but had an event to attend back in London.

Why it varies - example of another traveller

Did I need it all? No. I even threw out some clothing and stuff as I went.

Now at the same time, a friend was on a scooter doing the same trip (we met up occasionally). He had to pack so lightly that he had a total of 4 tshirts for the whole trip. Did he make it? Sure.

4-5 weeks is a decent length of time during which you can experience a variety of weather. Still, you can reuse stuff, buy more if you need it, and throw out as well. Basically, you can survive with a day pack if you really have to, or you can shove everything you own into a 120L superpack and lug that around - but you need to find the balance for yourself.

Would I pack the same way again?

If I did it again, I'd just take the same bags, because frankly I like them and have no need to buy new ones, but pack a bit lighter. For example I needed new shoes at one point, and it was actually quite fun trying to buy them in St Petersburg, given I speak no Russian :)


I think the choice of luggage very much depends on the type of trip you are planning to do. If you are doing standard backpacking trip, when you need to carry your stuff mainly for short distances from a hotel to a bus or train, then it makes sense to have a bigger backpack with more clothes/stuff to make your journey more comfortable, and have some spare room for the things you will buy on the way.

If you are planning to do a lot of hiking, or ride a scooter like Mark's friend, then I would definitely optimize for weight and pack ultra-light. When trying to keep the weight low, you need to buy a light-weight backpack. You would be surprised how heavy some of these 55l pack can be!


It depends. There are guys who have only 2 pair of socks (change if one get wet, one on feet, one is drying), 2 T-Shirts etc. On 1-week trip it can work, and it can, for sure, get you free compartment in the train, as no one will want to sit near you...

If you don't go so extreme, I can't honestly imagine packing for a few weeks in 55l backpack. There are simply too many things to be taken. At least one-week supply of socks, T-Shirts if you want to smell better as clochard, spare trousers (in case of heavy rain, falling into a stream or mud), 2 polars, rain-proof jacket, sandals, first aid kit, at least 1 big bottle of water and some food supplies (don't count on shop open in every village 24/7). You could also need a sleeping bag.

I'd say, 75l is a minimum, but buy as large backpack as you can. A backpack is never "too big", you don't have to load it at maximum, and the weight difference may be about 1kg (my 80l rucksack weights about 3kg) which is practically nothing (maybe unless you make an air travel, which is not the case). However, if the rucksack is too small, you're out of options.

There are people that go minimalistic but they are experts and they are limiting their luggage based on the experience from the previous trips. If you're asking here, you're not, so it's safer to take more than less.

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