Annual fuel savings calculator to buy a new car with better mpg's

[miles per year]/[Old mpg ave]-[miles per year]/[New mpg ave]*[Price per gall]=[$annual fuel savings]

Many of the smaller new cars are much nicer than they used to be. I sold a 12 year old Maxima that averaged 20mpg to buy a Fiesta that averages 35mpg. I assume the new $15000 car will last 12 years at 15k miles per year- so it costs $1250 per year. The fuels savings is $1220 per year. Not including all the other maintenance and repair variables, the fuel savings alone covers its cost.