Car Depreciation Calculator Formula

Understand the math behind the car depreciation calculator. Each variable explained with a worked example.

Formulas Used

Estimated Current Value

current_value = purchase_price * pow(1 - annual_depreciation_pct / 100, years_owned)

Total Depreciation

total_depreciation = purchase_price - purchase_price * pow(1 - annual_depreciation_pct / 100, years_owned)

Value Retained

value_retained_pct = pow(1 - annual_depreciation_pct / 100, years_owned) * 100

Variables

VariableDescriptionDefault
purchase_pricePurchase Price(USD)35000
years_ownedYears Owned(years)5
annual_depreciation_pctAnnual Depreciation Rate(%)15

How It Works

Car Depreciation Curve

Cars depreciate fastest in the first few years, then the rate of loss slows. A declining balance model captures this pattern.

Formula

Current Value = Purchase Price x (1 - Depreciation Rate)^Years

The average car loses 20% in the first year, then about 15% per year after that. After 5 years, a typical car retains about 37% of its original value.

Worked Example

A $35,000 car owned for 5 years at 15% annual depreciation.

purchase_price = 35000years_owned = 5annual_depreciation_pct = 15
  1. 01Current value = $35,000 x (0.85)^5 = $35,000 x 0.4437 = $15,530
  2. 02Total depreciation = $35,000 - $15,530 = $19,470
  3. 03Value retained = 44.4%

Ready to run the numbers?

Open Car Depreciation Calculator