How accurate would you say the PiP's MPG calculator is?

close enough for government work.

 

Based on the PiP MPG Spreadsheet that ukr2 maintains for some of us here:

Minimum difference: -28.48%
Maximum difference: 21.80%

Average difference: 4.39%

This was based on a sample size of 289 entries.

There are a few in there that probably should be tossed out, obviously (-28.48% difference??). But the average looks about right.

 

I have an average of a 3.89% difference, but that is over a smaller sample size.

Regardless...probably off by about 4% or a little more.

 

Prius Three 5630 miles -- display average 4.0% high Range 2.51% to 6.08% high
Plug-in Base 11290 miles -- display average 5.9% high Range 1.92% to 8.35% high
Its interesting that the Plug-in has a much wider variation as well as a higher average "error".

 

4% optimistic was about what I observed with the '04 over 160K miles, and the '11 over 30K miles.