Same as Donald's here on my HCH2. I have seen it as much as 2-3 MPG higher when calculated by hand, but usually 1-1.5 MPG better.

 

We have also been getting between .8-1.4 MPG higher than the displayed number.....I love this car!!!!

 

My girlfriend's 06 civic hybrid which was made in 09/05 one of the first

ones had the 62 mile bug fixed. since then it as been about 2 mpg off.

If it indicates 51 mpg by filling up to the same place, 'top of the tank to the
cap, actual mpg's will be 52.8-53.1, so about 2mpg's off.

so far with 2,500 miles with 62 mile bug fixed on trip 'A" which is ongoing
since the fix indicates 50.4 mpg which is in reality 52.4 mpg's.

great car. Gives my 03 vw jetta wagon tdi 5-speed competition.

alster

 

I have an '03, the display is very consistently about 7.5% optimistic. My last few tanks have indicated 44 or 45, and been about 41 or 42 respectively (stupid hills...). If you remember to factor in the error, the display is very precise so it's still good for determining real MPGs over known stretches of driving. There should be a way to recalibrate the meter though.

 

During my first two fill-ups, my HCHII dash read 1.4 and 1.2mpg lower than what I calculated. I always fill up to the first click.

For comparison:
Until just recently, I had not checked the accuracy of my Odyssey. The dash read ~0.7mpg lower than what I calculated after a recent fill-up.

I guess I will adjust, but it made for slightly pleasant surprises during these fill-ups. Otherwise, I would not have broken the 50mpg barrier.

 

On four tanks (one of which was a half-tank), I'm averaging about 2 mpg greater real fuel economy over FE indicated on the dash.

Aneil

 

My dash computer tends to show about 1-3 mpg less than what I'm actually getting by dividing odometer by gallons filled up. For example, my dash will show 40.5 mpg. However, I tend to fill up about 11 gallons after 475-480 miles which means I'm actually getting 43.18 to 43.63 mpg. Not that it really matters.

 

My displayed FE is always a little low, usually by about 2 MPG.

 

My '04 HCH MT overstates mileage by about 5 percent +/-. My trip B is lpmg and it reads 55.2 my calculated mpg is about 53.3. Remember, (at least on the '04), because the mpg is calculated on the metric system and coverted to English, there is a range that the actual reading can represent. 55.2 can mean 54.8 (last reading) to 55.6 (next reading).

 

I started to check my calculated mileage vs the display and discovered it would almost never match sometimes over and sometimes under. This led me to believe that I am never filling up in the exact same manner. There are too many variables involved, incline at the pump, pumps varying, the only sure way would be to park at the exact same pump in the exact same spot and fill up until you can see the gas at the top of the filler. If you put 500 miles and your fill up can vary by only a half gallon (which is quite easy to do) it can affect your mpg reading by 2 mpg or more. I have since quit comparing and rely on the display.