I read this question:

How to tell a colleague that I want to stop sharing the ride?

And I thought, maybe I don't pay my rideshare enough... Not the premise of that question, but it raised this question to me.

Taking into consideration:

  • I would take public transport if not for being offered a lift which mean ridesharing saves me $a per day.

  • Ridesharing gets me home around b minutes earlier.

  • I jump out along the way which means there are c meters of extra distance due to me.

  • The drive is long - d minutes, so that is certainly a factor.

  • We have a similar level role - grunts. But that should probably be taken into account - perhaps e pay difference.

What is a good way to calculate the amount to offer a colleague who driveshares with me accounting for a, b c, d, e and the x factor which would probably be friendship?

  • Why not just split the fuel bill? For wear and tear, you can just by the car owner lunch sometime.. once in a while
    – PagMax
    Commented Nov 30, 2018 at 2:29
  • Why oh why would anyone vote this down ?
    – Fattie
    Commented Nov 30, 2018 at 3:59
  • @PagMax - my goodness, fuel is the LEAST EXPENSIVE cost of providing a rideshare. Imagine if you could use a taxi and pay only for the fuel!!
    – Fattie
    Commented Nov 30, 2018 at 3:59
  • 1
    @Fattie Except OP is not taking a taxi. I thought that was the difference between Taxi and rideshare.. the other colleague is not trying to run a business on providing rides and you just a want to ensure he doesn’t have to spend from his pocket..! Rest is all your personal dynamics.
    – PagMax
    Commented Nov 30, 2018 at 4:10
  • For clarification, I'm in Australia. The trip is from outer suburbs to a country town, 60 km and around 45 minutes.
    – Coomie
    Commented Nov 30, 2018 at 5:20

4 Answers 4


In the US, there is a simple way to estimate the total cost without a lot of bookkeeping. The IRS has standard mileage rates for deducting business use of an automobile.

The 2018 business use rate, which includes cost of ownership, is 54.5 cents per mile. The moving rate, which only includes variable costs, is 18 cents per mile. I suggest picking one of those, or something in between, and paying half the IRS mileage rate.

  • 1
    My goodness! 55 cents a mile is really unrealistic, P.S. What you're talking about there is an absolute wholesale rate. Say that you had a car and I rode with you literally all the time for some reason and we drove all around the nation. Sure, then you could use a "50 cent" type rate. {Indeed the only way that "whacky example" could happen is if ..... we were business partners on the vehicle: which is essentially what the rate is for.} There's no way that on a short 'retail" use (1 to 20 miles commute) you could pay someone only that much!!! Surely?!
    – Fattie
    Commented Nov 30, 2018 at 4:05
  • 6
    @Fattie 55 cents per mile is totally realistic for a typical journey. It includes the cost of insurance, depreciation of the car value, tyre wear, fuel and servicing costs attributable to that journey. For example, the last 4 cars that I have had depreciated at almost exactly £0.10 per mile over the time that I owned them.
    – uɐɪ
    Commented Nov 30, 2018 at 10:43
  • 1
    So at 0.66 AUD per km, 120km per day, on average your friend has spent $80 on everything (fuel, repairs, cost of the car, everything). If the variable costs proportion is the same in Australia than the IRS think it is in the states, that's just under $30. I don't know if this is the right way to do it, but the answer is suggesting you pay between 15 and 40 bucks, but closer to 40. How does this compare to public transport @coomie?
    – Nathan
    Commented Nov 30, 2018 at 12:24

Stop guessing, just ask

The only person who can really tell you how much it costs them, and how much they expect contributed - is the person you're ridesharing with.

Offering a specific amount risks either undervaluing them, or if the offer is higher than they'd expect - making them feel obligated to keep ridesharing with you.

Instead of trying to do any specific calculation, just mention that you are conscious there are a lot of hidden costs in running a car (including their time) and that you don't want them to feel like a bus service. Ask them to give you a number that they honestly feel covers the cost, and let them know that if circumstances ever change - they should just let you know.

  • It's a good point. one problem is that most folks would underestimate the cost.
    – Fattie
    Commented Nov 30, 2018 at 12:12

Just expanding the point I made in comment as an answer. (Thank @Fattie for suggesting).

To me obvious thing is to share the fuel cost. (Calculating cost based on distance you are riding and the average fuel efficiency of that car's model and make). While calculating, always give benefit-of-doubt and rounding-off benefit to the car owner because there is some wear and tear on their car as well.

Having worked in different countries (but not ride-sharing), I know in general no one wants to make money from these arrangements. They just want to help out and feel good about making a difference on traffic and pollution situation. So I do no think you should compare it to taxi.

Also, no point in using hypothetical numbers as in how much money you would have spent if you would have taken public transport or how many minutes earlier or later you could have reached. You pay for how you are travelling now and not based how you could have travelled.

Also, another nice thing to do would be, once in a while may be buy them a lunch or invite them over for lunch (Depending on local culture at your location) to show your appreciation for the effort they are taking.

  • 1
    Good answer. I can appreciate your point "You only want to cover costs". But to repeat what I said above, the cost of fuel is nothing. Simply find out from friend (1) daily cost of insurance (2) cost of repairs for the year, divided by 200 business days and (3) monthly cost of the loan (or whatever equivalent) divided by 20 business days. Add up 1, 2, 3 to get the daily cost. (the fuel is nothing, don't even worry about it.)
    – Fattie
    Commented Nov 30, 2018 at 5:18
  • 6
    @Fattie what do you mean with "cost of fuel is nothing" ? I basically spend twice the amount I spend for insurance on fuel costs myself.
    – Laurent S.
    Commented Nov 30, 2018 at 10:38
  • Cost is deprecation, maintenance, repairs, insurance, and fuel. A lot more than just fuel.
    – gnasher729
    Commented Nov 30, 2018 at 21:36

An easy answer is,

Use a taxi one day

and get that exact figure. 1

The problem is you then have to calculate how much better it is to have your friend chauffeur you: it is much more convenient for you than a taxi.

So, multiply by say 1.5x or 2x.

One issue is I'm not sure whether you should use a "normal" taxi price or an "uber" price, which is usually less.

An issue with this...

This is sort of the "business" way to do it. But. It is very unrealistic.

  • Say you are riding with friend every day
  • Indeed it's likely that is the main use of the vehicle of friend
  • Say you are paying via the formula mentioned above

Now, say that friend has a sudden repair - $900 for a new gearbox

  • if you want to be "officious" about it, you would say "Oh, of course the amount I have been paying you every day includes such depreciation and a sinking cost factor. That guy on the internet said so. So, tough tittie for you! I'm not contributing a cent to the ghearbox! pick me up tomrorow ok!"

Of course, in reality you can't do that - in the example you have to give the guy half the cost of the new gearbox.

So the short answer is:

  1. about what it would cost you to take a taxi

  2. realistically as a polite person, you'll pay half of any "exceptional" costs that come up

1 PagMax pointed out that of the taxi fare, a small amount is the taxi driver's earnings. (Maybe 20%.) Some people might feel that the share driver "shouldn't get" that.

  • 3
    I might have found a flaw in your calculation: I estimated the cost of a taxi using an online tool: $113 per trip. If I double that it becomes cheaper for me to not work than ride home. And then you want me to pay additional costs on top?
    – Coomie
    Commented Nov 30, 2018 at 5:10
  • Hi @coomie - go ahead and purchase and support a car, then? About how long (miles/time) is the ride in question?
    – Fattie
    Commented Nov 30, 2018 at 5:14
  • For sure in some cities, taxis are super expensive (eg, London black cabs). What's the cost of a "minicab" or uber in your example? What about a "share uber" (if your city has those).
    – Fattie
    Commented Nov 30, 2018 at 5:15
  • 7
    This is a bit of a weird comparison. When you pay for a taxi you pay for their time (because you aren't sharing the ride, they are transporting you). You also pay for their downtime to provide a constant service to take you wherever (which I assume the OP's friend doesn't provide). You pay for them potentially to have to double back in order to get a new fair (depending on location, but, remember you aren't sharing a ride). If I was giving the OP a ride, I'd appreciate a contribution, but I'm not a taxi.
    – Nathan
    Commented Nov 30, 2018 at 11:57
  • I can see you've edited your answer to guess what amount of the fare applies to the vehicle (and associated non-labour costs), but if that's your argument, why is it better to start guessing from a taxi fair than a standard mileage allowance?
    – Nathan
    Commented Nov 30, 2018 at 12:01

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .