When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
After reading this tread here are my opinion on MPG calculation.
For example
600 miles / 30 gallons= 20mpg
600 miles /33 gallons= 18.2 mpg
I seen many people suggest that this is the case.
But consider this. The only time it will give consistent results is when you fill up at exacle the same gas station at exactly the same spot with exactly the same technique and even then unless you have a see throug fuel tank to be able to tell that it fill up to exact levels MPG calculation will fluctuate.
Just like my example above.
My MPG range is anywhere from 15-19 MPG.