How much should she charge per kilometer?

Question

My mother-in-law does not own a car, and expects my wife to drive her everywhere; including back and forth to work, which is 25km each way. With gas at $1.35 per liter, it's not cheap. Also, my wife's four cylinder economy car requires maintenance; we had to put new tires on it this year, and spent over $500 repairing the air conditioning. There's always something that comes up, and the more she drives it, the more stuff wears out.

We can't afford for my wife to drive her everywhere for free anymore, so we decided that a per-kilometer charge is only fair. We don't want to profit from her dear Mom. How much should we expect to charge per kilometer of travel?

Answer 1

i would'nt, I would just keep track of the miles she uses and ask her to contribute to the petrol or fill the tank up here and there! giving a family member an itemised bill each week/month sounds like its only going to cause resentment and troubles down the line, where as chipping in for running costs along the way is far more buddy like and  friendly.

Answer 2

$0.35/km. The US Fed says 58.8/Mi, so that should be about right, due to rate of exchange.