Hello, I have a '13 Prius Persona. It is driving me crazy how the $ savings is actually calculated. I input how much gas costs on each fill up, but I have no idea what the car is calculating my savings against. (example: When I turn my car off, it says I saved $3.12- but compared to what?) Thanks for any help with this. Derrick
Try this link and scroll down to page 235. Hope this helps http://www.toyota.com/t3Portal/document/om/OM47791U/pdf/sec_02-02.pdf