To determine travel distance until empty, use your average mpg, (if you do not know your miles per gallon use the mpg calculator) and the remaining gallons of fuel (which can be estimated if you know your car's gas tank capacity and if your car is half full for example) input both fiels to calculate an estimated travel distance left until your empty of gas.
That a performance car can sometimes be more fuel efficient than a hybrid car depending on the users driving style. Even though your car may read zero miles until empty, most modern cars have a reserve. Check your owner manual for the volume capacity of your vehicle. To avoid running out of gas always refuel before or by 0 miles fuel remaining.