What size rucksack do you use to commute?

I'm starting to cycle to work and wondering what size rucksack to go for.

I have a 65L hiking rucksack already but I reckon that might be a little bit too big.

What do you use?

30 litre Karrimor Hot with a liner. Or a pannier bag depending on the bike.

Medium size panniers.

A 25L pannier

An Altura Urban pannier

65Litres is way too big. My 40litre is also too big and my carrying 2 or 3st in it is also silly. Buy a small bag and don't carry so much stuff.

Used panniers for a while, but gone back to a 25litre Vaude. Drive in on Friday and take shirts etc in for the following week, easy.

30 litre dakine bag thinks its a 101. looks a bit like a schoolbag, but it's excellent, comfy, lots of pockets and plenty of protection for llaptops etc. love it.

25l Camelbak on Mondays with a weeks clothing in, then everything in jersey pockets for the rest of the week. I iz roadie 🙂

camelbak hoss for me. 23ltr waterproof.

A 25L pannier

20L Quechua one and a beam rack with drybag if too small. SOmetimes (if its been a wet day at work, or I forgot something) a 40L old Lowe alpine..

18 litre Agu pannier.

I use a Camelback Octane 8 for my commute, most of the time its big enough for what I need to carry (towel a fresh set of cycling gear for the ride home and some other odds and ends) but if I need more space I just have to undo the centre zip and I gain a few more litres of space.

Camelback HAWG here

camelbak mule for me

Leave stuff at work and just take a rack pack on the top of the pannier

I'm not sure if it's 65 or 45 litre but it is too big.

I have a 25 litre karrimor bag but I don't think I will get a change of clothes and my dinner in it.

I think mine is 30L, it's an Ogio backpack/hydration pack. Enough room for trousers,shoes,polo shirt, small repair kit,some water/snackbars, waterproof.