How accurate is the dashboard MPG?

Yeah Wayne Gerdes (Clean MPG founder) noted the mpg display was accurate, on his pre-production 2016 Prius review car. It was scheduled to be crushed, after journalists were done with it.

 

Yep, that’s the exact thing I was thinking of. Indicates they are able to make it accurate if they really desire it to be.

 

My spreadsheet, with what, 188 fill ups now, indicates “accurately inaccurate”, specifically:
relentlessly optimistic, but in a fairly narrow zone, anywhere between 5-10%, with median around 7.5.

 

just now my computer stays on 4.2 L/km , but in real with 45.7 Litters I did 1025 km = 4.45
(i have auris hybrid not prius)

 

Yeah with me if it’s for example saying 4.5, calculated is invariably 4.8 (liters per 100 km), sometimes 4.9.