miles until light is on?

when i am driving my car which is a 91 t.c. i see the line less then a quater tank of gas, onces it hit the gas light is on. my qestion is that how many miles can my car go when the gas light is on? i use only regular unleaded gasoline. thanks

if ur light goes on at a quarter tank its messed, cuz mine turns on after the bottom line, but u can travel many many miles on with the light on, my friend said 100, but idunno, i know my gass guage pin has cut the E in half and still was goin so dont worry if the lights on