I am considering a Prius and have read many posts about mileage and it seems like 42MPG is a average real world normal driving result acieved by Prius owners.<br>I would drive about 50/50 city and highway miles in a midwestern climate.<br><br>If the majority of Prius owners are seeing better than 42 avg. mpg I would like to know. I am only interested in results that are based on total fuel used and not what is displayed on the screen in the Prius.

Howdy,<br><br>I've been driven my Prius for about 13,000 miles now, and based on calculations of actually fuel used, I'm getting slightly better than 43 mpg. <br><br>I would have gotten better overall mileage had it<br>not been for a trip from the S.F. Bay Area to San Diego, which included a lot of speeding and <br>generally poor driving habits. <br><br>I generally get better than 45 mpg weekly with a daily highway commute of about 28 miles each way.<br>With really careful driving (no hard accelerating, keeping it at 65mph) I have gotten 50 mpg.<br><br>Hope this helps!

Yikes! I should check my grammar before posting a message!<br><br>Another point: I've noticed the estimated mpg shown on the Prius display usually varies less than 10% by my calculated mpg (distance travelled divided by fuel added). About every other fueling, the estimated mpg has a less than one mpg difference from my calculated mpg.

Though my sample size is short, my 1200 miles have avergaed 51.4 on mixed driving (about 600 miles on highway and 600 miles in city).

You should also keep in mind that the bladder int eh fuel tank may make calculations at fill-up imprecise.

&gt;&gt;&gt;23 Prius owners who have kept track of their miles driven and total gas consumed. In summary, the totals were 209,000 miles and 4740 gallons for an average of 44.0 mpg.&lt;&lt;&lt;<br><br>Keep in mind, too, that existing data is mostly from the colder months, since most of us didn't get our cars till after September. Averages should increase significantly over this summer. Even here on the NW coast, where frosts are a rarity, I'm noticing a ten percent improvement with the warmer weather.<br><br>-- PeterD

I am averaging about 45 mpg -- mostly city driving on relatively flat terrain. Much depends on the outside temperature, use of A/C and heat, and the number of "cold starts" versus "warm starts." My mileage improved after the first thousand miles, although I'm not sure whether it was a "break in" period for the Prius or the driver.

On our first three fillups at the same pump we got 39.0, 39.7 and 43 mpg, all in mostly city less than 5 mile trips. There has been some messages stating that mpg increases with mileage. So far, we could not argue with that (or, we are getting better at driving this Prius).

In Message 5980 meatgenius asked:<br>&gt; I am considering a Prius and have read many <br>&gt; posts about mileage and it seems like 42MPG is <br>&gt; a average real world normal driving result <br>&gt; achieved by Prius owners.<br>Looks more like 44.5 MPG to me.<br><a href=http://groups.yahoo.com/group/toyota-prius/surveys?id=685153 target=new>http://groups.yahoo.com/group/toyota-prius/surveys?id=685153</a><br><\ br>&gt; I would drive about 50/50 city and highway <br>&gt; miles in a midwestern climate.<br>Depends on 50% of what!<br>I drive 72 miles R/T each day:<br>- First 3 miles at &lt; 45<br>- Five minute coffee stop,<br>- Next 12 miles at 55-60 with 12 (possible) stoplights.<br>- I287 for 17 miles at 65++ (75 is _NO_ problem - except for NOT going that fast.<br>- Final 4 miles (with stoplights) at 40.<br>Home is reversed but with nasty traffic and higher speeds - usually - or 5 and 10 mile traffic jams otherwise. :-(<br>In the WINTER, with careful (opportunistic) driving, I saw 53 MPG once, 50 on most attempts and 45+ "just driving it".<br><br>This spring - "just driving it", I'm at 48 MPG _EVERY_DAY_ I commute, with 36 to 45 MPG in town on the weekends.<br><br>It's the DISTANCE that matters: 50/50 for 10 miles a day and you should be in an EV.<br>If you drive MORE than 15 minutes at a time, then you WILL SEE 45+ MPG without hardly trying.<br>If you "take opportunities", 50+ is readily achieved - ONCE Prius is warmed up!<br><br>Almost 13,000 miles (ulp!) and STILL in love!<br>Bill Powell - NJ "HALFGAS"<br>(Prius: Just Drive It!)

In Message 5989 avalpert2000 mentioned:<br>&gt; You should also keep in mind that the bladder <br>&gt; int eh fuel tank may make calculations at fill-<br>&gt; up imprecise. <br>It doesn't matter:<br>By _LAW_, fuel pumps must be calibrated.<br>Even if there is "inadvertent error" my money goes with the error being in the station's favor: pump says 7 gal but actually delivers 6.93 gal.<br><br>-You fill the tank and note the current mileage.<br><br>-You fill it up again and note the delta mileage and the pump gallons. This is the MPG for the previous tank.<br><br>-Repeat (but not very often) :-)<br><br>After 13,000 miles at 48+ MPG, I just bet that either "pump errors" have averaged out or I have dumped a LOT of gasoline on the pavement somewhere.<br><br>Over 13,000 miles and STILL in love,<br>Bill Powell - NJ "HALFGAS"<br>(Prius: Just Drive It!)

It was my understanding that the Prius' tank does not neccesarily take the same amount of gas every time. So if you fill it full to 11.9, drive 595 (50 MPG) miles and fill up again. The tank this time may be 'full' at 11 due to temperature changes contracting the bladder, in which case you will think you only used 11 gallons with 54.09 MPG. If I am misunderstanding how the bladder works I am sorry.

You are right that the gas station fill-up method of calculating mileage will have errors due to the variable bladder volume. After several tanks however, the errors will average out and this method will give very accurate results. After all, what really matters is the total miles that you drive on the total amount of gas that you put in the car.<br><br>This is why the survey taken on the egroups site was very interesting. The 23 people that had been keeping track of their mileage had put an average of 9000 miles on their Prius. By 9000 miles, the tank-to-tank variations are averaged out and do not effect the results.<br><br>Chuck

That amkes snes, over time the course of time the bladder expands and cotnracts such that it has some 'typical' storage capacity. And the amoung of gallons put in/ miles driven on any one tank would average out. Now, can we reverse that number and figure out based on the mileage driven and the typical mpg someone is getting what the typical fuel capacity is?

That makes sense, over the course of time the bladder expands and cotnracts such that it has some 'typical' storage capacity. And the amount of gallons put in/miles driven on any one tank would average out. Now, can we reverse that number and figure out based on the mileage driven and the typical mpg someone is getting what the typical fuel capacity is?

&gt;-You fill the tank and note the current mileage.<br>&gt;<br>&gt;-You fill it up again and note the delta mileage &gt;and the pump gallons. This is the MPG for the &gt;previous tank.<br><br>Bill, I'm sure you realize this, but for the benefit of shorter-timers who are reading this: The problem with a single reading using this method is that the amount that you use to fill up the tank is not necessarily the same amount that you used in the last tankful because the tank can, in effect, change size. It contains a bladder that expands and contracts to reduce emissions, and said bladder may not expand as much when filled one time as another depending on the temp and other factors.<br><br>Over time, it surely averages out, of course.<br><br>Burns

&gt; Over time, it surely averages out, of course.<br><br>It more than just "averages out". If you are accumulating the total amount of gas you've put in your vehicle, and computing the MPG based on all the miles you've travelled during that time, then the only error you are getting is how much the tank has shrunk or grown the LAST time you filled up. So if we assume an error of +- 1 gallon when you fill up, the accumulated error after 10 tank fill ups would be less than a 1 percent error, and that error gets smaller with every fillup since it's always 1 gallon out of &lt;total number of gallons put in the car&gt;.<br><br>-DanC

In Message 6040 avalpert2000 asked:<br>&lt;snip&gt;<br>&gt; Now, can we reverse that number and figure out <br>&gt; based on the mileage driven and the typical mpg <br>&gt; someone is getting what the typical fuel <br>&gt; capacity is? <br>Only if you regularly perform the "Acme Battery Test". :-)

In Message 6055 Burns_Fisher replied:<br>&gt; It contains a bladder that expands and <br>&gt; contracts to reduce emissions, and said bladder <br>&gt; may not expand as much when filled one time as <br>&gt; another depending on the temp and other factors.<br>&gt; Over time, it surely averages out, of course.<br>Ah! As I said: Repeat.<br>The interesting thing is that with spill and fill, we are ALL probably getting BETTER mileage than we calculate because of gas pump calibration that "favor" the station by the max "error" the law permits.<br>I suspect that the on-screen is actually correct in the long run.<br><br>Whatever . . <br>I'm still gettiong much more than twice the MPG I got from my T-Bird with NO loss of comfort, handling or in-traffic performance.<br><br>Gotta LOVE it!<br>bp