How to compute mileage (mpg)?

You have to do it over a long period of time (many tank fulls) and then estimate the beginning fuel level the very first time. Any error in estimating the beginning fuel level the first time will be minimized when looking at 10 or more tanks of gas to calculate the mileage.

Fill the tank and record the mileage.

The next time you need gas, fill the tank and record the mileage. Subtract the second mileage from the first mileage. Divide the result by the amount of gas (gallons and tenths) purchased the second time.

You can use the trip odometer if you have one. Reset when you fill up the first time. When you refill, record the miles traveled, and divide by the gallons purchased.

It's very simple.

Fill your tank at a given station to a given point (say, the second time the nozzle clicks off). Reset your trip odometer or note the mileage reading.

Drive the car. The longer you drive it, the more accurate will be your mileage calculation.

Return to the same gas station -- use the same pump if possible. Fill the tank once again to the same point as before (say, the second time the nozzle clicks off). Note the number of litres or gallons, and the odometer reading.

Divide the number of miles you travelled by the number of gallons you purchased. That is your fuel mileage (in miles per gallon) for that tank of fuel.

OR

Multiply the number of litres you bought by 100, then divide the result by the number of kilometres you travelled. That is your fuel mileage (in litres/100km) for that tank of fuel.

1. Fill Tank.
2. Record mileage.
3. Drive car till near empty.
4. Fill tank again. Use same pump at same station. Let the auto shutoff system work. (Do this on initial fillup too. Record gallons to fill
5. Record mileage.

Erich

Just ignore the first tank. Fill up the tank and note the mileage. After that, so long as you fill up and note the mileage each time, the amount of fuel it take to fill up is the amount used since the fill up, so simply divide the miles since the last fill up by the amount it took to fill up the tank and you have your miles per gallon.

As Mark says, do it over many fill ups to get an accurate average. I usually note whether the driving between fill ups is local or highway, as there will usually be a distinct difference in MPG between the two.

Merritt

"newbie7" wrote: > It may seem like a superfluous question, but what is the best > way of > calculating what mmg yuor vehicle is getting? I have my miles > reading > of course, and I can record how much gas I put in, but there > was some > gas already there in the tank, and how do I know what was > traveled on > how much gas? If you have a good system, please share!

Also, lacking a trip meter, record miles on odometer at fillup, take a new reading at next fillup and subtract the old reading from the new reading and then divide the result by the gallons used.

Amazing. Our educational system on display.

I agree wholeheartedly davidj92

Fill the tank, record the mileage, run the tank down. Fill it again. Subtract the mileage at the first fill from the mileage at the second filling. Divide that figure by the amount of fuel consumed. If that is too complicated ask your math professor for additional help after class, WBMA

mike hunt

Newly wrote:

You are just kidding this guy right? ;)

mike hunt

Mark A wrote:

Do you expect him to drive backward? LOL

mike hunt

Randy wrote:

What if he is traveling cross country? ;)

mike hunt

Kathy and Erich Co>

Sad isn't it. It is like asking a person for directions and he tells you to go south past my dads house then turn right. If you get to my brothers house your are three blocks past it. LOL

mike hunt

No Spam wrote:

It is not necessary to return to the same gas station and the same pump to calculate fuel mileage. Most fuel pumps are regulated by the local government's bureau of weights and measures so my guess is that the amount of fuel recorded as delivered to the tank should be close enough for fuel economy calculation purposes.

Monitoring fuel mileage is more useful to see a trend, not so much individual tanks. You will find over time, with the same driver in the same road conditions, fuel mileage is going to be fairly consistent, within 2 or

Fill tank, reset trip odometer or record actual mileage.

Drive.

Refill tank. For most accurate results, use the same pump parked in the same position. If you routinely "top off" then do so by the same number of "clicks".

Record number of gallons.

Read trip mileage, or record actual mileage.

Subtract old mileage reading from new mileage reading... should match trip mileage.

Miles per gallon equals miles/gallons... miles divided by gallons, or, for example, you went 340 miles on 19 gallons, then your MPG is

To the good advice given elsewhere in the thread, I would add, "check your speedometer" (and thus your odometer). These things have some intrinsic error, which might either stack up atop or the other potential source of error: hanges you have made by tire/wheel size.

Knowing how much and in which direction your speedometer is fibbing can save you from tickets, too!

A few runs past one of those radar "sleds" at a steady and easily readable speed should suffice, although finding a stopwatch, or a wristwatch with a sweep second hand, and timing yourself through a measured mile or a "speedometer test section" on the freeway is the classic way of doing it.

You can easily see how recordkeeping can combine with the aspects of fillup discipline mentioned by others to let you partial out highway from city from all-around mileage.

If all you want is a good horseback guess, the fillup practices are probably the most important aspect, unless your speedometer is way off.

Also, the study should be conducted over a span of time longer than a couple of tankfuls but shorter than a season (differences in driving habits as the weather changes, and in some areas differences in gasoline formulation, can affect mileage). Cheers,

--Joe

: Sad isn't it. It is like asking a person for directions and he : tells you to go south past my dads house then turn right. If : you get to my brothers house your are three blocks past it. LOL : >

: > Amazing. Our educational system on display.

I don't think OP needs help with division or what to divide into what. I interpreted his question as: how to estimate the # of gallons consumed over a measured distance? I myself wonder just how accurate the auto shut-off mechanism is for this purpose. But it gives an estimate.

In the end, I care not so much about the most accurate mpg number (I mean, what am I going to do, not buy groceries or drive to see my family if mpg is x instead of y?), but about getting a warning if it is consistently worse than usual.

I was amazed the other day when I had a chance to work with a brother (16) and sister (14) at a concession stand. They both would have worked circles around almost every adult that works there.

Oh, the reason - parents own a store.