Yes, Bass sizes are described in fractions. Just about everyone eventually plays a 3/4. No, really! 4/4 basses do exist, but they are mostly just too big for ordinary mortals. So I and most others play 3/4 basses, with a string length between 41" and 42.5".
But of course smaller basses do exist, in 1/2, 1/4, 1/8, 1/10 and even 1/16! Sadly the smaller you go, the harder it is to get a nice bass sound because the strings are just too short. But you have to start somewhere.
The best way to find out what size bass you need is to come into the shop and try them.
Half size basses
These are suitable for teenagers and smaller adults. String length is typically around 39" - 40"
Quarter Size Basses
These basses are for kids not yet big enough for a 1/2 size bass!
Yes, I can supply smaller basses, but I don't keep a lot of stock, they are usually ordered in specially.
All our basses, all sizes, get the same careful setup and attention.