Car depreciation calculator
A car bought for 30,000 that loses 15% of its value each year is worth 13,311.16 after 5 years, or 44.3705% of its price, after 16,688.84 of depreciation. Enter the price, the yearly rate and the years owned. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Purchase price
- 30,000
- Annual rate
- 15
- Years
- 5
- Current value
- 13,311.16
- Total depreciation
- 16,688.84
- Remaining percent
- 44.3705
A car's market value rarely stays at the sticker after you drive it off the lot. Insurance desks, private-sale listings, refinance quotes, and personal-finance spreadsheets all need a reproducible current value from three numbers: what you paid, how fast the vehicle loses value each year, and how long you have owned it. This car depreciation calculator applies the declining-balance model used in retail auto guides: each year the remaining value is multiplied by one minus the annual rate. Enter the purchase price, the annual depreciation rate as a percent, and the years owned, and the tool returns the current value together with the total depreciation and the remaining share of the original price. A negative rate is rejected because appreciation is not depreciation.
How declining-balance car depreciation is calculated
Retail auto guides and many insurer residual tables treat a passenger car as losing a fixed share of whatever value remains at the start of each year, not a fixed dollar amount. That is the declining-balance, or reducing-balance, model. The current value V is then P times one minus r, raised to the power n.
After one year a thirty-thousand car at fifteen percent is worth twenty-five thousand five hundred; after a second year the same fifteen percent is taken from that remaining balance, not from the original sticker, so the drop is smaller in dollars even though the rate is unchanged. After five years the factor is zero point eight five to the fifth, about forty-four percent of the purchase price.
When the annual rate is exactly zero the car keeps its purchase price for every n, which is the honest answer for a promotional no-loss assumption or a collectible you are treating as flat. When n is zero the owner has just taken delivery and V equals P. A one-hundred percent rate writes the vehicle off after the first year and returns zero for any positive n.
Where a car depreciation calculator earns its keep
Private sellers and marketplace listings need a reproducible asking-price floor from the sticker, the advertised annual loss rate, and the model-year age, not a teaser that hides the compounding. Insurance and refinance desks use the same three numbers when they want a quick actual-cash-value sanity check before they pull a full valuation book. Failed validation does not consume balance.
Keep requests small, pin the rounded currency fields in tests, and you get stable compound-depreciation math for widgets, quote checkers, and edge workers without standing up a full residual-valuation system of your own.
What you can do with it
Private-sale asking price
Enter what you paid, a typical annual loss rate from a consumer guide, and the years you have owned the car to set a current-value floor before you list it.
FAQ
What happens if the depreciation rate is negative?
A negative rate would be appreciation, and this calculator only models depreciation. Zero is allowed and leaves the purchase price unchanged.
Does this include mileage, condition, or tax depreciation?
No. The calculator returns only the declining-balance residual from price, rate, and years. Mileage bands, accident history, MACRS tax tables, and loan payoff belong in separate estimates.
Why does my car lose less money each year at the same rate?
Because each year's percentage is taken from what the car is still worth, not from the original price. After the first year, the same 15% applies to a smaller value, so the yearly drop in money shrinks even though the rate stays the same.
Can I enter part of a year for how long I have owned the car?
Yes. Fractions such as 2.5 years are accepted, up to 100 years. If you enter zero years, you have just taken delivery and the current value equals the purchase price.
What do a 0% or a 100% depreciation rate mean?
At 0% the car keeps its purchase price for any number of years, which suits a collectible you treat as holding its value. At 100% the car is written off after the first year and its value is zero.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/fin/car-depreciation \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"purchase_price":30000,"annual_rate":15,"years":5}'const res = await fetch("https://api.kit.forhosting.com/fin/car-depreciation", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"purchase_price": 30000,
"annual_rate": 15,
"years": 5
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/fin/car-depreciation",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"purchase_price": 30000,
"annual_rate": 15,
"years": 5
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/fin/car-depreciation", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"purchase_price":30000,"annual_rate":15,"years":5}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"purchase_price":30000,"annual_rate":15,"years":5}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/fin/car-depreciation", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"purchase_price": 30000,
"annual_rate": 15,
"years": 5
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "fin.car_depreciation",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_purchase_price | 1000000000000000 |
max_years | 100 |
max_annual_rate | 100 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
How declining-balance car depreciation is calculated
Convert the quoted annual depreciation rate into a decimal r equal to annual_rate divided by one hundred, let P be the purchase price, and let n be the years owned.
Input contract, typical rates, and validation
The calculator does not model mileage bands, accident history, option packages, regional demand, sales tax, or loan payoff; those belong in dedicated tools. Pair this residual with your own payoff and insurance actual-cash-value checks when you need a sell-or-keep decision. POST a JSON body with three required fields. purchase_price is what you paid for the car in currency units and must be a finite number greater than zero. A zero or negative price fails with invalid_input naming purchase_price and is not billed, because a free or inverted purchase is not a residual problem. annual_rate is the annual depreciation rate as a percent: use 15 for fifteen percent per year, not 0.15, and it must be a finite number from zero through one hundred. A negative annual_rate fails with invalid_input because a depreciation rate below zero would be appreciation and this tool does not invent a growth model. years is how long the car has been owned; fractions such as two point five are allowed, and the value must be a finite number greater than or equal to zero and at most one hundred. Missing fields, non-finite values, a purchase price that is not positive, years below zero, and a rate above one hundred also fail with invalid_input naming the problem. On success the body echoes purchase_price, annual_rate, and years; returns current_value as the declining-balance residual; total_depreciation as purchase_price minus that residual; remaining_percent as the share of the original price still on the books; and a short formula string you can show next to the numbers. Typical passenger-car rates in consumer guides sit near twenty percent in the first year and ten to fifteen percent thereafter; this calculator uses one constant annual rate for the whole holding period, so if you want a steeper first year, run year one at twenty percent and feed that current value back as the next purchase_price.
Where a car depreciation calculator earns its keep
Classroom finance lessons and fleet-budget scripts batch many purchase prices, rates, and holding periods through the JSON API when they need an oracle rather than a spreadsheet cell that silently uses straight-line instead of declining balance. Used-car shoppers often compare a three-year-old hatchback with a five-year-old sedan at the same rate; feeding each age directly makes the extra two years visible as a lower current_value instead of a hidden table lookup.
Integration use cases
Insurance and refinance sanity checks
Compare a quoted actual cash value or refinance residual against a declining-balance current_value from the same purchase price, rate, and age.
Fleet budgets and finance lessons
Call the JSON API with many price, rate, and years triples when a classroom or fleet script needs a deterministic car-depreciation oracle instead of a spreadsheet cell.
Technical questions
How do I calculate a car's depreciated value?
Send purchase_price (what you paid), annual_rate as a percent (e.g. 15), and years owned. The API returns current_value = purchase_price × (1 − annual_rate/100)^years, plus total_depreciation and remaining_percent.
Is annual_rate a percent or a decimal fraction?
A percent. Use 15 for a 15% annual loss, not 0.15. The engine divides by 100 before raising (1 − r) to the years owned.
What does the car depreciation calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.