New vs Old Car Cost Calculator — Purchase, Fuel, Maintenance, Insurance, Depreciation

What’s included in this New vs Old Car Cost Calculator?

This side-by-side tool estimates the total cost of ownership over your chosen horizon. It models up-front purchase or down payment, monthly loan payments (if financed), fuel or electricity based on efficiency and energy prices, maintenance & repairs, insurance, registration/other fees, and a terminal resale value net of selling costs and any remaining loan payoff. We discount all annual cash flows to today at your selected rate to get an NPV of costs, then convert that NPV into an Equivalent Annual Cost (EAC) to make year-by-year comparisons simple. Cost-per-mile is shown using both discounted (EAC / average miles) and undiscounted views.

Depreciation is captured economically: rather than a separate non-cash line, the calculator uses the initial purchase and the expected resale value at the end of the horizon. You can set resale via % retained at T, an annual depreciation rate, or enter a direct value. Efficiency supports MPG, L/100km, or kWh/100km; just provide the matching fuel/electric price and an expected annual growth rate if needed.

Informational only — not financial advice. Energy prices, maintenance, and resale vary by market and condition.

Thinking about switching cars? How to read the numbers in this comparison

Changing cars involves far more than the sticker price. This calculator estimates Total Cost of Ownership (TCO) for a new versus an old car by modeling the key cash flows you’ll actually pay: purchase or down payment, monthly finance costs (if any), fuel or electricity, maintenance & repairs, insurance, registration/road fees, and the net proceeds when you sell the car at the end of your horizon. It then discounts those cash flows to today to produce an NPV of costs, converts that into an Equivalent Annual Cost (EAC), and shows cost per mile so you can compare options on equal footing.

What each input represents (and why it matters)

• Horizon & mileage: Years you plan to keep the car and your miles driven each year (with optional growth). Higher mileage amplifies differences in fuel/energy and maintenance; lower mileage emphasises insurance and depreciation.
• Purchase & financing: We model the drive-away price (vehicle price + sales tax + fees − incentives − trade-in). If financed, only the down payment occurs at time 0; the monthly payment stream is added over the term, and any remaining loan payoff is subtracted from your resale proceeds at the end.
• Fuel or electricity: Choose MPG, L/100km, or kWh/100km and a unit price. You can apply an annual price growth rate to stress-test rising energy costs and see how an efficient new car or EV might catch up.
• Maintenance & repairs: Year-1 values with an annual growth rate. New cars often benefit from warranty periods and lower failure risk; older cars can have steeper growth as components age.
• Insurance, registration, other: Enter typical annual amounts and growth. Insurance can be higher for brand-new vehicles but may fall with better safety tech; registration and road fees vary by region and emissions banding.
• Resale value: Set a % retained at the horizon, an annual depreciation rate, or a direct value; include selling costs. Tip: Don’t add a separate “depreciation” line—purchase + resale already captures value loss.

How to interpret the outputs

NPV of costs discounts all future cash flows at your chosen rate r to reflect time value (opportunity cost and risk). EAC spreads that NPV evenly across years so you can compare annualised ownership costs: EAC = NPV × [ r(1+r)^T / ((1+r)^T − 1) ] if r > 0. The calculator also reports discounted cost per mile (EAC ÷ average annual miles) and an undiscounted cost-per-mile for a simple, cash-only perspective.

When a “new” car can be cheaper overall

• High annual mileage: Better efficiency (or EV energy costs) and fewer repairs can outweigh higher purchase price.
• Long horizon: Lower maintenance, longer warranty coverage, and stronger residuals help the new car’s NPV.
• Volatile fuel prices: If you expect prices to rise, efficient options gain ground—use the price growth input to test scenarios.

When an “old” car often wins

• Low mileage / short horizon: You won’t “use up” the new car’s benefits; the lower up-front outlay dominates.
• Favourable insurance & taxes: In some regions, older cars can be cheaper to insure/register (but watch emissions/ULEZ-style charges).
• Confident maintenance planning: If you know the vehicle’s condition and budget realistically for repairs, the old car can remain compelling.

Practical tips

• Keep a single currency and time basis (all annual figures) for consistency.
• Include local “other” costs (parking permits, tolls, congestion/clean-air zones) in the Other annual field.
• Sensitivity-test mileage, energy price growth, and residual % to see where the break-even flips.

This tool is educational and 100% client-side. Real-world outcomes vary by market, driving habits, and vehicle condition—verify key assumptions before making decisions.