Fuel savings vs total cost calculator

[Sporkman]

Hi,

If anybody's interested, I wrote a calculator to compare cost of ownership between two cars with different initial costs & fuel efficiency:

http://sporkforge.com/finance/gas_cost.php

It also does time discounting of future costs.

[GasSavers_Dust]

Interesting. Thanks for it. I tried comparing the newer cars I am looking at to just my car, and the break even point is 10+ years.

only driving 468 miles (750 km) per month and $6 for gas should even it out, but even the cheapest car and the car I want break even in almost 3 years.

[Sporkman]

Originally Posted by Dust

only driving 468 miles (750 km) per month and $6 for gas should even it out, but even the cheapest car and the car I want break even in almost 3 years.

The thing is, cars differ in price by thousands of dollars, but fuel economy savings run in the hundreds of dollars per year, so you'd want a pretty significant fuel economy advantage to justify a higher car price.

[Erdrick]

Sporkman: Thanks a lot for the calculator tool that you wrote. An excellent first post! Most people come here asking for help, but you jumped on and immediately starting helping! A warm welcome to you, my friend! Get a gaslog started and get ready to save gas!

Do you have any plans on adding more variables to your formulas? Perhaps allowing users to look at electric car costs?

I tried entering a negative value, and the program still worked, so that was good. Whether my thinking on this is correct or not could be debated, I think that entering a negative value is a good test. Let's say you have a car worth $4000. Holding on to that car, you have possession of something worth $4000. Selling it would get you $4000... and while typing this I realized my error. If you already own your vehicle, and you are considering just sticking it out in the vehicle you already own, it wouldn't make sense to use a negative number. You would just use 0 for cost.

I just ran a situation where I would a) keep my 1998 Jetta TDi, or get a new Polo TDi -- if they are ever released in America. The calculations ran off the charts. Do you have any plans to extend the timescale past 10 years? It probably wouldn't make sense for a purchase decision, but it would be neat to be able to see the math worked out. Not many people keep a main car for 20 years but....

[GasSavers_Red]

Very cool little app. Welcome to GS

[Sporkman]

Originally Posted by Erdrick

Do you have any plans on adding more variables to your formulas? Perhaps allowing users to look at electric car costs?

Well there's always maintenance, taxes, insurance, resale value, "utility" re cargo capacity, etc, but those are a lot more difficult to figure in in this context.

Originally Posted by Erdrick

I just ran a situation where I would a) keep my 1998 Jetta TDi, or get a new Polo TDi -- if they are ever released in America. The calculations ran off the charts. Do you have any plans to extend the timescale past 10 years? It probably wouldn't make sense for a purchase decision, but it would be neat to be able to see the math worked out. Not many people keep a main car for 20 years but....

The calculations ran off the charts because technically you should subtract the resale values at the end of the time span (the new car would have a much higher resale value then your old one), though keeping the old car would still be the better deal.

I capped it at 10 years because (a) that's a practical time horizon, (b) to save on runtime, as I use a simple linear search for the breakeven point, and (c) to keep the yearly cost summary to about a page width...

[Sporkman]

Originally Posted by Red

Very cool little app. Welcome to GS

Thanks!

[Tepco]

Great job on the calculator!!

I just realized that if i rode my bike to work for a year and saved my gas money, i could buy a new car, well used really.

Ok maybe thats exagerating a little but i really have to get a car thats better on gas.

[Snax]

Bookmarked!

Thanks!

[BumblingB]

GOOD JOB! Nice - Thanks!