How to tell how much gas is left 1999 Kawasaki ZX6r?

[lilbigdog789]

I have a 1999 Kawasaki NInja zx6r and I trying to find out if I'll get some type of light or something if I am about to run out of gas. Can I install something that will tell me if not?

 

[Fluttershy]

ya you can take it to a shop and they could put it on, or you could just pull over ever so often and look in the tank