Payoff Calculator
 

I'm not good at math.

I've never made a spreadsheet.

If I understand spreadsheets correctly, they can calculate stuff. I was thinking a spreadsheet would be handy to calculate how long a mod would take to break even. You'd type in your current mpg, the cost of the mod, the cost of gas, the expected mpg improvement,...am I forgetting anything? And then, blammo, it'd spit out the answer as 'payoff in X miles' and it'd help you decide if the mod is worth it. Anybody here good with spreadsheets?

I've never made a spreadsheet.

I'm not good at math.

:o

Here is something I came up with a while back. Input your info into the yellow fields to get the info. It tells you money saved via mpg increase. You could simply subtract the cost of the mod from the savings to get an estimated answer.

You can use or ignore the second set of info. I simply duplicated it because I have two main vehicles.

gas_calc.xls

Thanks, Daox. That's along the lines of what I was thinking. I'll see if I can figure out how to tweak it to give a break even point. The old dog/new tricks thing, you know. :rolleyes:

I tried to make a break even spreadsheet the other day for some stuff I'll be testing on EcoRenovator. I found it quite challenging to find a way to actually get it to just spit out a number for me. I ended up using two data sets and graphed the info on a chart. This seemed to be the easiest way to do it. It also gives you a good idea of your savings after the break even point which is nice.

I made one myself, and I know there's a way to make two separate graphs interact... (I just to a course on this stuff!!!) But I can't remember. Guess it's time to get out the textbook. Wow, something I learned in class is actually applicable to real life!! woo hoo!!

Here's my original spreadsheet, change the numbers as you wish, it's comparing my two main vehicles. The second chart is to see when my metro would pay for itself in gas savings (depending on how much I would pay for it, I made this before I bought my car)