7 ms·

Show HN: Car Cost Calculator – my weekend project

48 points by khet 12y ago

sixQuarks 12y ago
Where did you get a 20-30% average depreciation on cars? Depreciation is not linear on vehicles. Most of the depreciation occurs in the first few years and then tapers off. Is this calculated into your algorithm?
- mgolawala 12y ago
  scroll down. He explains his algorithm : "The caclulator uses exponential depreciation is used to calclate the cost of depreciation and the asset value of a car over time" That sounds like a fair way to do it.
- jeffasinger 12y ago
  It looks like the 20% is 20% of the value that year, so it looks like value is shown with exponential decay. So if a car starts out at $20,000 it will be worth $16,000 the next year, $12,800 after the second year, and $10,240 after the third. Notice that around the third year, the decrease in value slows considerably.
  - pkulak 12y ago
    Yup. And I'd say that's pretty accurate.
- khet 12y ago
  I'm using an exponential depreciation function to calculate the cost of the car in time. The car loses most of it's value during the first few years.
- OrwellianChild 12y ago
  While I'm fine with exponential depreciation, the rates are very high (or maybe just variable by car). My RAV4 has closer to 9-10% depreciation (assuming 15k miles/year) per the Edmunds TCO mentioned elsewhere. May be constructive to look up your individual car and input it into khet's calculator. Kudos for giving us the option. May be helpful flag inputs that are highly deterministic of the output and suggest look-ups.
  - uncoder0 12y ago
    Yeah I actually have an outlier that has negative depreciation. Got it used for 26k with 44k miles. 6 Months later my insurance company informed me that they had to put my car value closer to 32k due to replacement costs and that this may go up over my ownership of the car.
- phamilton 12y ago
  That's actually not true, at least not always. I did some analysis on KBB for a car I was looking to buy. I found that for my particular model, depreciation between years 1, 2 and 3 were far less than between 3, 4 and 5. There's a graph on http://www.undiscoveredfeatures.com/2011/09/kelly-blue-book.html http://www.undiscoveredfeatures.com/2011/09/kelly-blue-book.... that shows the relationship.
emeltzz 12y ago
You might add a parking cost field, because for anyone in a city, parking's unlikely to be free
zdrummond 12y ago
Nice idea, but I actually think Edmund's TCO is a bit more comprehensive and uses real world data for each car. http://www.edmunds.com/porsche/911/2011/tco.html?style=101380348 http://www.edmunds.com/porsche/911/2011/tco.html?style=10138...
- OrwellianChild 12y ago
  Nice aspirational example there with the 911... Didn't know about TCO, but I like the idea. First glance impressions of the Edmunds tool: - Mileage assumes 15k/year, which may not be accurate for a large part of the population (I only drive 10k/year, which affects depreciation, maintenance, etc.) - The math governing financing is opaque, as is maintenance and repairs. I'd like to know what they're assuming will break, need service, etc. Esp. because it's non-linear. Not sure how I'm going to accrue $500 in maintenance in the first year on my 2012 Rav4 - all it needs are oil changes (3 x $30). - Insurance also strikes me as astonishingly high (over double what I'd pay/year). All of this is to say, I see the value of a more flexible and transparent calculator to meet individual needs...
  - maxerickson 12y ago
    There's a reasonably high chance that you will need to replace the tires fairly soon after buying a used car (which is how I read it working). That's most of that $500.
- dang 12y ago
  > Nice idea, but I actually think Edmund's TCO is a bit more comprehensive It would be astonishing if that weren't the case: one is a weekend hack while the other is a major product in the space. A good Show HN discussion should engage with a project at its own level. When a comment is too critical, or raises the bar too high, it tends to shut the discussion down (i.e. why bother). Our goal in these threads should be to foster further creativity. I'm speaking generally—don't mean to pick on one comment (and certainly not to impugn your intent). It's more that this is on our minds a lot right now, and we'll probably post something much more detailed about it.
bitJericho 12y ago
Don't the maintenance costs go up after a while. Otherwise people would only buy 10 year old cars as they'd be like 20-30k cheaper :D
- khet 12y ago
  The problem there is, I have no idea how to model maintenance costs! The field is basically a hack. If there is a better way, I'd like to do that.
  - bitJericho 12y ago
    It looks like AAA releases some data about that: http://newsroom.aaa.com/2013/04/cost-of-owning-and-operating-vehicle-in-u-s-increases-nearly-two-percent-according-to-aaas-2013-your-driving-costs-study/ http://newsroom.aaa.com/2013/04/cost-of-owning-and-operating... That said, I would never endorse AAA to provide money to. They were horrible towards me as a claimant.
  - rzt 12y ago
    It's also model-contingent and sometimes luck. My SAAB has required about $1,600 a year for repairs and maintenance in the past three years I've owned it, but my wife's Honda Element has required only new tires ($500) and brake rotors and pads ($200, DIY install) since it rolled off the assembly line.
  - OrwellianChild 12y ago
    Depends on how deep you want to go, but you could set up a table with common considerations and let users set frequency... Most maintenance is mileage-dependent, so if you base your schedule on their monthly mileage, it could look like: Repair Cost Frequency ------ ---- --------- Oil Change $30 5000 mi Tires $500 45000 mi Battery $150 30000 mi Timing Belt $1500 60000 mi Misc $200 15000 mi Do the math in impact/year and input that cost into your table...
    - 12y ago
Istof 12y ago
I would be curious to see this versus an electric car cost calculator
- sebnukem2 12y ago
  You could approximate by saying that a gallon is a kWh of energy. set up the Fuel Price per Gallon to electricity cost $0.1(a), 3(b) MPG, and a much lower maintenance cost... (a) 10 cents per kWh (depends on where you live), (b) 3 miles per kWh (or 333Wh/mile, depends on the actual EV)
  - altcognito 12y ago
    > and a much lower maintenance cost... As long as your figures include replacing the batteries every so often....
timjahn 12y ago
The default gas price is shown as $3.40/gallon. Where are you getting gas that cheap??
- nilkn 12y ago
  That's pretty typical for Houston at least.
  - timjahn 12y ago
    Wow, that's amazing. Was $4.17 in Chicago when I filled up a few days ago.
    - adrinavarro 12y ago
      Ah, the 8$ per gallon price in Europe. And I find it affordable…
- khet 12y ago
  It's $1.97 where I live (Dubai). You should see what that does to the traffic!
  - obilgic 12y ago
    Just paid $4.99 in LA last night.
- Zircom 12y ago
  Texas, probably. It's been hovering between 3.40-3.60 the past couple months.
deleted 12y ago
[deleted]
sergnech 12y ago
Good idea, unfortunately barely usable on my ipad - entry text fields are too slow
gedrap 12y ago
The other week I was thinking about buying a car to save money on commuting... And I'm sure I am not the only one. I definitely see value in this tool. I have 0 experience with cars, and I am sure I have no idea how much does it cost to maintain, repair. Again, I don't think I am the only one. So is £20 or so worth paying to get accurate numbers, tweaked for a specific country, with nice explanations why and how? I think so ;) I would really consider experimenting to see if this could be monetized, whether people are willing to pay. It won't make millions, but as a passive income source? That might work.
sebnukem2 12y ago
such caclulator. very caclate.
korzun 12y ago
Like someone else mentioned, there are better tools to calculate static ownership costs. This is definitely a good start. I'm working on https://www.maintenr.com https://www.maintenr.com and we allow you to calculate your service and fuel expenses dynamicly.
- darksim905 12y ago
  Could you explain what your planned features are & who your target audience is? The 'tutorials', will you have any generic ones for people to use or a repository of them? Can the tutorials be made public vs private? This is interesting & I signed up just to see what it's about. I don't do my own work on my car but I knew a few mechanics & I understand the 'process' of how to do certain things with my vehicle. I also keep a pretty detailed record of the work I do on my car. Neat!
  - korzun 12y ago
    Target audience will be shifting towards general market. I focused on enthusiasts at first as I know that market very well. Tutorials can be private and could be shared if you wish; we offer 'export' functionality. Down the line, as we collect more data (makes things interesting) there is a plan to introduce some sort of crowd sourcing aspect. Feel free to bug me if you have any questions! Thanks for checking it out.
pcl 12y ago
This is a great tool! It'd be awesome to add lease information into it as well, to help with the lease-vs-buy decision.
- officialjunk 12y ago
  I too would like to evaluate lease versus buy.
xexers 12y ago
Thanks! Feature suggestion: Metric units (for every other country that is not the USA)
- guidedlight 12y ago
  I completely agree. This tool is useless to me in Australia, unless I convert all the units. Even within the same measurement system different countries express units in different ways (e.g. Imperial Gallon vs US Gallon; and MPG, L/100km & Km/Litre).

48 points by khet 12y ago

Where did you get a 20-30% average depreciation on cars? Depreciation is not linear on vehicles. Most of the depreciation occurs in the first few years and then tapers off. Is this calculated into your algorithm?

mgolawala 12y ago
scroll down. He explains his algorithm : "The caclulator uses exponential depreciation is used to calclate the cost of depreciation and the asset value of a car over time" That sounds like a fair way to do it.
jeffasinger 12y ago
It looks like the 20% is 20% of the value that year, so it looks like value is shown with exponential decay. So if a car starts out at $20,000 it will be worth $16,000 the next year, $12,800 after the second year, and $10,240 after the third. Notice that around the third year, the decrease in value slows considerably.
- pkulak 12y ago
  Yup. And I'd say that's pretty accurate.
khet 12y ago
I'm using an exponential depreciation function to calculate the cost of the car in time. The car loses most of it's value during the first few years.
OrwellianChild 12y ago
While I'm fine with exponential depreciation, the rates are very high (or maybe just variable by car). My RAV4 has closer to 9-10% depreciation (assuming 15k miles/year) per the Edmunds TCO mentioned elsewhere. May be constructive to look up your individual car and input it into khet's calculator. Kudos for giving us the option. May be helpful flag inputs that are highly deterministic of the output and suggest look-ups.
- uncoder0 12y ago
  Yeah I actually have an outlier that has negative depreciation. Got it used for 26k with 44k miles. 6 Months later my insurance company informed me that they had to put my car value closer to 32k due to replacement costs and that this may go up over my ownership of the car.
phamilton 12y ago
That's actually not true, at least not always. I did some analysis on KBB for a car I was looking to buy. I found that for my particular model, depreciation between years 1, 2 and 3 were far less than between 3, 4 and 5. There's a graph on http://www.undiscoveredfeatures.com/2011/09/kelly-blue-book.html http://www.undiscoveredfeatures.com/2011/09/kelly-blue-book.... that shows the relationship.

emeltzz 12y ago

You might add a parking cost field, because for anyone in a city, parking's unlikely to be free

zdrummond 12y ago

Nice idea, but I actually think Edmund's TCO is a bit more comprehensive and uses real world data for each car. http://www.edmunds.com/porsche/911/2011/tco.html?style=101380348 http://www.edmunds.com/porsche/911/2011/tco.html?style=10138...

OrwellianChild 12y ago
Nice aspirational example there with the 911... Didn't know about TCO, but I like the idea. First glance impressions of the Edmunds tool: - Mileage assumes 15k/year, which may not be accurate for a large part of the population (I only drive 10k/year, which affects depreciation, maintenance, etc.) - The math governing financing is opaque, as is maintenance and repairs. I'd like to know what they're assuming will break, need service, etc. Esp. because it's non-linear. Not sure how I'm going to accrue $500 in maintenance in the first year on my 2012 Rav4 - all it needs are oil changes (3 x $30). - Insurance also strikes me as astonishingly high (over double what I'd pay/year). All of this is to say, I see the value of a more flexible and transparent calculator to meet individual needs...
- maxerickson 12y ago
  There's a reasonably high chance that you will need to replace the tires fairly soon after buying a used car (which is how I read it working). That's most of that $500.
dang 12y ago
> Nice idea, but I actually think Edmund's TCO is a bit more comprehensive It would be astonishing if that weren't the case: one is a weekend hack while the other is a major product in the space. A good Show HN discussion should engage with a project at its own level. When a comment is too critical, or raises the bar too high, it tends to shut the discussion down (i.e. why bother). Our goal in these threads should be to foster further creativity. I'm speaking generally—don't mean to pick on one comment (and certainly not to impugn your intent). It's more that this is on our minds a lot right now, and we'll probably post something much more detailed about it.

bitJericho 12y ago

Don't the maintenance costs go up after a while. Otherwise people would only buy 10 year old cars as they'd be like 20-30k cheaper :D

khet 12y ago
The problem there is, I have no idea how to model maintenance costs! The field is basically a hack. If there is a better way, I'd like to do that.
- bitJericho 12y ago
  It looks like AAA releases some data about that: http://newsroom.aaa.com/2013/04/cost-of-owning-and-operating-vehicle-in-u-s-increases-nearly-two-percent-according-to-aaas-2013-your-driving-costs-study/ http://newsroom.aaa.com/2013/04/cost-of-owning-and-operating... That said, I would never endorse AAA to provide money to. They were horrible towards me as a claimant.
- rzt 12y ago
  It's also model-contingent and sometimes luck. My SAAB has required about $1,600 a year for repairs and maintenance in the past three years I've owned it, but my wife's Honda Element has required only new tires ($500) and brake rotors and pads ($200, DIY install) since it rolled off the assembly line.
- OrwellianChild 12y ago
  Depends on how deep you want to go, but you could set up a table with common considerations and let users set frequency... Most maintenance is mileage-dependent, so if you base your schedule on their monthly mileage, it could look like: Repair Cost Frequency ------ ---- --------- Oil Change $30 5000 mi Tires $500 45000 mi Battery $150 30000 mi Timing Belt $1500 60000 mi Misc $200 15000 mi Do the math in impact/year and input that cost into your table...
  - 12y ago

Istof 12y ago

I would be curious to see this versus an electric car cost calculator

sebnukem2 12y ago
You could approximate by saying that a gallon is a kWh of energy. set up the Fuel Price per Gallon to electricity cost $0.1(a), 3(b) MPG, and a much lower maintenance cost... (a) 10 cents per kWh (depends on where you live), (b) 3 miles per kWh (or 333Wh/mile, depends on the actual EV)
- altcognito 12y ago
  > and a much lower maintenance cost... As long as your figures include replacing the batteries every so often....

timjahn 12y ago

The default gas price is shown as $3.40/gallon. Where are you getting gas that cheap??

nilkn 12y ago
That's pretty typical for Houston at least.
- timjahn 12y ago
  Wow, that's amazing. Was $4.17 in Chicago when I filled up a few days ago.
  - adrinavarro 12y ago
    Ah, the 8$ per gallon price in Europe. And I find it affordable…
khet 12y ago
It's $1.97 where I live (Dubai). You should see what that does to the traffic!
- obilgic 12y ago
  Just paid $4.99 in LA last night.
Zircom 12y ago
Texas, probably. It's been hovering between 3.40-3.60 the past couple months.

deleted 12y ago

[deleted]

sergnech 12y ago

Good idea, unfortunately barely usable on my ipad - entry text fields are too slow

gedrap 12y ago

The other week I was thinking about buying a car to save money on commuting... And I'm sure I am not the only one. I definitely see value in this tool. I have 0 experience with cars, and I am sure I have no idea how much does it cost to maintain, repair. Again, I don't think I am the only one. So is £20 or so worth paying to get accurate numbers, tweaked for a specific country, with nice explanations why and how? I think so ;) I would really consider experimenting to see if this could be monetized, whether people are willing to pay. It won't make millions, but as a passive income source? That might work.

sebnukem2 12y ago

such caclulator. very caclate.

korzun 12y ago

Like someone else mentioned, there are better tools to calculate static ownership costs. This is definitely a good start. I'm working on https://www.maintenr.com https://www.maintenr.com and we allow you to calculate your service and fuel expenses dynamicly.

darksim905 12y ago
Could you explain what your planned features are & who your target audience is? The 'tutorials', will you have any generic ones for people to use or a repository of them? Can the tutorials be made public vs private? This is interesting & I signed up just to see what it's about. I don't do my own work on my car but I knew a few mechanics & I understand the 'process' of how to do certain things with my vehicle. I also keep a pretty detailed record of the work I do on my car. Neat!
- korzun 12y ago
  Target audience will be shifting towards general market. I focused on enthusiasts at first as I know that market very well. Tutorials can be private and could be shared if you wish; we offer 'export' functionality. Down the line, as we collect more data (makes things interesting) there is a plan to introduce some sort of crowd sourcing aspect. Feel free to bug me if you have any questions! Thanks for checking it out.

pcl 12y ago

This is a great tool! It'd be awesome to add lease information into it as well, to help with the lease-vs-buy decision.

officialjunk 12y ago
I too would like to evaluate lease versus buy.

xexers 12y ago

Thanks! Feature suggestion: Metric units (for every other country that is not the USA)

guidedlight 12y ago
I completely agree. This tool is useless to me in Australia, unless I convert all the units. Even within the same measurement system different countries express units in different ways (e.g. Imperial Gallon vs US Gallon; and MPG, L/100km & Km/Litre).