What size cage is correct for two guinea pigs?

for a common mouse you buy at the pet store? id reccommend at lleast a 20 gallon tank, others may find this inaccurate but i like to actually give my pets room to run and be happy.

i had two rats a few years back and kept them in a tank about 55 gallons.

so the answer is, as big as you can have. 1 mouse would more than happy in a 20-30 gallon tank though. just remember, bigger is better with caging a pet.