No one said there would be any math !!!!
Well I sort of knew there would be math, but I didnt know how much.
The first bit is pretty simple. Figuring out your MPG’s (Miles Per gallon)
To do this you need to first fill up your tank and record your mileage and drive.
When it comes time to fill up again, take note of your current mileage, and how many gallons it took to re-fill the gas tank.
Now subtract your beginning miles from the the current mileage.
If you have an odometer you could have zeroed it when you first got gas and check it again when you fill up. Either way the end result is the number of miles you drove on that tank of gas.
Now take the total miles driven for that tank and divide it by the number of gallons it just took to fill up. Here is my last tank full as an example.
Starting mileage: 55714.5
Ending mileage: 56061.9
Mileage driven: 344.4
Total gallons: 8.354
So you have 344.4/8.354 = 41.2 mpg Not bad for simply slowing down huh?
But is knowing your MPG enough? How about your DPM? or GPD?
What are these you say. Hows Dollars Per Mile or Gallons Per Day.
These are pretty important to fully understand what your impact on not only your wallet, but the environment as well.
For Dollars Per Mile, the formula is much like the one for MPG. I’ll once again use my last fill up as an example. 244.4 miles and $28.56 to fill. Take 28.56/344.4 and get .08 cents per mile for this tank full.
Take the numbers over a month to see a monthly average.
For the month of April I drove 2517 miles. I used 67.584 gallons. And spent $244.29.
This gives me a DPM of .097 cents per mile.
Looking at this number another way, it costs me $5.24 to drive one way to work !!!!!
Now for Gallons Per Day.
With an 41.4 MPG 4 days between fill ups and 344.4 total miles and 8.354 Gallons.
Take 8.354/4 for 2.088 Gallons per day.
For the month again 77.992/27 for 2.888 gallons per day.
So we have for the month of April
Average MPG of 37.24
Average DPM of .097 cents
Average GPD of 2.888 gallons
So what do these numbers mean? Well we want to have MPG as High as Possible and if that number is high then the DPM will naturally be lower. Because you will be driving more miles on less gas. Which means I am spending less money on fuel.
If the MPG is high there is also a better chance of having the GPD low, but this number also depends upon how many miles that you put on the car in a given number of days.
It looks a bit confusing, but it really isn’t. I keep a steno book in the car and write down the mileage, gallons and cost of every tank full.
If I can do this, any one can.
So start keeping track of these things and you will be off to a great start on lowering what you are paying at the pump. In order to know if you are saving anything you need to keep track.
Find out more at Sipping Fuel
Wednesday, May 7th, 2008
