MPG Calculator

After filling up last night I was slightly interested to see how my mpg was looking - I'm not particularly bothered as it won't affect how much I drive the car.
(Now where's that flame suit ))

Anyway I averaged 21 mpg since last fill

 

I tend not to look to avoid disappointment

 

MPG calculator!!

Why not just work it out

4.55 litres to the gallon is a good enough approximation even for tree huggers

 

25mpg

 

I'm getting a constant 15.5MPG.

200 miles to a tank, 60 litre tank (I think, 03 WRX)

Somebody please tell me I'm burning way too much fuel? Or is this normal?

My motor is running 340 BHP, STI 8 bottom end, VF34 etc etc...