Is A5 or B5 the better size for a bullet journal?

A5 (roughly 5.8 x 8.3 inches) is the portable standard most journalers default to and dominates this pool. B5 is noticeably larger and gives more room for elaborate weekly spreads or two-page layouts, at the cost of pocketability. Choose A5 for carry-everywhere use and B5 if you do detailed planning at a desk.