Easiest way is what was said above, and what I do...and most people. Just fill up your tank, going to the same station helps...even be anal and go to the same pump and dont forget to reset your trip. Drive for however long..I usually run it all the way down, then fill up again and divide the miles on your trip by the amount of gallons you put in.

 

Yes, simply Miles Per Gallon = X miles / gallons at fill up.

 

My computer on the car read 38.8 MPG at my last fillup. I have a program on my IPod called Gas Hog, in which I input mileage and gallons of gas put in at Fill-up. My Ipod registered 38.2 MPG. I am really pleased I just picked up the car on Thursday and have been driving it at various speeds as the dealer told me to refrain from using the cruise control or driving the same speed for very long for the first 500 miles. I had a 4 1/2 drive home from the dealer and I so wanted to use the cruise.

 

Keep in mind it has nothing to do with your mph, it all has to do with engine speed (rpms). Rev it at different rpms, including redline, but rev it slowly.

 

Just took a trip in my Sport AT up to the mountains and got 33.9mpg while the computer said ~36 so mine is also off by ~2mpg.

 

I still fail to understand how I account for the remaining gas. I'm blind on this one or something.

 

The remaining doesn't matter.

If I fill up my tank then I am at 100% (not really but for the sake of argument) of the amount of fuel my car can hold.

Then if I drive 200 miles and I'm about a half of a tank, then I fill up and on the gas pump it says I've put in 5 gallons then my MPG is 40.

I've used 5 gallons to go 200 miles.

 

Ignore what you have left. It's what you have used that is important. You can take a quick reading at any point, by putting your tank back to full and counting your miles. No it's not 100% accurate - the only way to do that would be to get a container exactly the same size as your tank, fill that up from a gas pump to be sure you are getting exactly the right amount (some pumps cheat you - big surprise), transfer the full tank into your gas tank, drive until there is no gas left in your tank, and then count your miles. We can't do that, so we trust the pump and calculate what we have used before we fill up again.

If you are like me, and you fill up at different stations, depending on the going price, you will probably be a few MPG off in the best case scenario. It's more of an art and less of a science. You can get all anal about it, and use the same pump and try to be really careful about how much you put in, and it will be a little more accurate.

 

Ah okay I understand now, I have no idea why it was so unclear before.

 

From tank to tank - because different pumps have different cut-off points, you may not be getting an exactly correct mpg rating, but over time, you can figure your mpg very accurately. Say your odometer reads 10,000 miles and you've kept track of every fill-up, and you've put 300 gallons of fuel in it. Your mpg's for the life of the vehicle to that point would be 33.3.

I used to have a diesel VW, and I'd fill the tank up until I could see the fuel - like a quarter inch more and it would start to flow down the side of my car. If you fill it like that evey time, assuming the pump is accurately telling you how much fuel you pumped in, you can figure your mpg's per tank exactly also.

 

So is the built in Avg MPG calculator fairly accruate? If so then holy cow am I excited. Like others, I'm seeing 37.4 to 37.8 MPG around town!

I think I may be trading in my Yaris for one of these babies.

The car outclasses the Yaris! I'm sad to say this because I love my Yaris, but truly there is no comparison. With MPGs like this the Fit may actually out do the Yaris in MPG as well.

The gauges at night are just spectacular! I love the USB stereo as well. Sounds so good. I do get an "unsupported" message every so often though.

 

Most are reporting the trip computer AVG MPG is 5-10% higher than the actual/calculated MPG.

 

So a solid 34 to 35 MPG in the city. I can live with that! OUTSTANDING!

I may be selling my Yaris sooooonnnn...

I would love a 09 Fit Sport Navi with Orange Revolution Metallic.

 

Today was my first mostly highway tank. I got 38 mpg calculated and it read 40.9 on computer. I was in bumper to bumper traffic for about an hour of the tank and when there was no traffic I averaged about 10 over the limit. I have a MT, about 1,200 miles on car, and tires at 33 lbs.

I'm very happy with these results. Much better than I expected. I drive down to Chicago from my town in Wisconsin about every other week and it is about 180 miles one way. In my 4Runner I was spending about $80 per trip. I'm now spending less than $35. Very nice!

 

I have a black yaris and now a blue fit...there are things I like about both better. But if I had to choose, it would be the fit. The yaris is paid off now, but even if I traded it in I would still have to finance a little bit...and I really don't want to

 

Sport AT: after 782 miles I am getting 32.05mpg in conservative mixed driving.
The dash computer overestimates by 11%

 

Ok 1st tank results are in (FINALLY!!!)

475.9 miles on the trip meter (light came on at 423)
12.512 gal That filler tube holds some fuel!
42.4 MPG on the Fit meter
38.0 Hand calculated
4.4 mpg difference about 11% over (about par with other results)

Didn't mean to go that far on a tank but GEES! I had NO CHOICE! There is simply NO GAS north of ATLANTA! 1 station in 10 got gas!!!

No kidding RATIONING is in effect. $20 limits! at about 4.19 a gallon! It took 3 stations and about 3 hrs. to fill a FIT!

Anyways... as particular as honda is, it suprises me that their mpg meters are consistantly about 10% off on everyonse car. Almost like they planned it? Did they really figure we wouldn't catch on?

Since it's based on the on board computer, hopefully Honda has a fix in place to correct the skewed meter.

 

I just got back from picking up my new black Fit.

After driving it exactly 100 miles all interstate, my meter stated 42mpg. I put exactly 2.64 gallons.

So hand calculated, I was getting 38.46.

No wind, night time, 70 degrees, 40% humidity, no gear except for a extra large soda from BK. I weigh 165lbs.

Cruise locked at 70 mph. No traffic never slowed down or accelerated, just changed lanes several times.

Fit have total of 157 miles now. 7 miles when I picked it up, put about 35 miles of test drive, 8 miles from dealership to gas station.

I am very impress with MPG.

 

Well on my third tank of gas I got a calculated 36.5mpg, I think the car computed just a little under 40. 80% fwy driving on the 5 which is mostly traffic.

 

I found out the salesman had filled up the tank without resetting the trip computer. This was making my numbers higher than normal. I topped it off last night and reset. Now I'm seeing about 35 and some change. No too shabby this is mixed city and hwy. I am very pleased!
It does seem to keep climbing. This is even with some hard accelleration a couple of times.