Hi,
I don't have my Prius yet (It is scheduled to arrive in 2 weeks !) but I am reading this site a bit obsessively as I wait for it to arrive. One thing I am curious about is how you all determine the mpg you are getting. I test drove a Prius and did see a MPG number on the large display screen on the dash, but it was constantly changing as I drove. Is there a reading on the dash that tells MPG per trip, or per tank? Since I refill my tank somewhere between empty and 1/4 tank, how would I calc the actual milage if I divided miles/tank of gas, since I don't really know exactly how many gallons I have used? Do you have to estimate the amount of gas used when you calculate the mpg?
Thanks for any information. I am looking forward to seeing what mpg I can achieve.

The Prius has mutliple display screens. The Energy display shows instantaneous fuel economy and the flow of energy through the hybrid system. The Consumption screen shows instantaneous fuel economy and graphs average mileage over 5 minute intervals. On the bottom of that same screen, you'll find tank distance and fuel economy.

If the car doesn't have a mileage display, you can use the miles for the just-completed tank over the amount of gallons used to fill for that tank (earlier). However, this is really only accurate long-term over many tanks.

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Let me get you to a thread that has discussed this same question.

Go To: (Honda Civic Hybrid) "Forum" Click on it
Go down to the thread: (How Do You Determine MPG) by myndreach "Click"
Go To Post #9 by Tigerhonaker

I hope this helps but the easier way would be the way "Jason" is saying to read the different displays and let the Prius Computer Do the work and computations. Good-Luck and many happy MPG

HTH

Terry

The Prius II actually has an [annoying] feature that resets the tank average when you fill it up, so it's easy to keep track on a tank-by-tank basis, but you have to remember to write down the data (or remember it) before it resets!

2001 Prius Photos       2005 Prius Photos
1992 Mitsubishi Delica Diesel-WVO Hybrid Photos

I think there is only one realistic way : note the gallons and the miles (i allways reset the odometer "A", there are two you can reset individually) at every tank. I use the receipt for making notes, and enter the data either in a spreadsheet, or on this website.

The meters in the car are only an inidication, and i have found that it is on the (very) optimistic side.

Thanks all ! When I read the post that tigerhonaker refered me to, I had a "doh!" moment, guess it was obvious but it hadn't occured to me as I am new to all of this.

Thanks again all for the replies.

Hey Kim; Glad we could help and I hope when you read through the thread that I told you about that it made since and was some help.

Terry

BTW; if you are still unclear on method you can click on my name and send me a E-Mail and I will take the time to try to really make it clear. It's kinda confusing at first. Take-Care