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When does replacing your car beat keeping it?

Find the exact month when keeping your old car stops being the smart financial move. Model maintenance escalation, new-car depreciation drag, and HYSA opportunity cost.

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Your Current Car

7
85000

Is the car paid off?

Maintenance Cost Trend

10% annual growth is realistic for a car 7–10 years old. High mileage (>100k) automatically applies a 1.25× multiplier.

New Car Alternative

Vehicle class
60

Recommendation:

Keep your car

Keeping saves $52,844 over the 60-month horizon.

Over the next 60 months, keeping your current car saves approximately $52,844 compared to replacing it now. Your maintenance costs — even with growth — stay below the new car's depreciation drag and loan payments. Check back when your monthly maintenance climbs above $570.

Monthly cost: keep vs replace

Incremental costs only — insurance, fuel, and registration are equal on both paths and excluded. The vertical line marks the crossover point.

Cumulative cost over 60 months

Which path costs less in total by each month. The paths may cross once the new car's depreciation drag fades.

Key numbers

Current car value (now)
$15,000
Estimated original MSRP
$38,244
Net equity from selling now
$15,000
New car monthly loan payment
$768/mo
Total keep cost (60 mo)
$24,407
Total replace cost (60 mo)
$77,251
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How it works

Both paths — keep and replace — involve owning a car. The tool isolates the incremental costs unique to each choice, so shared expenses (insurance, fuel, registration) cancel out of the comparison.

Keep cost per month: escalating maintenance (base × (1 + annual growth)^(m/12)) plus the monthly depreciation loss on your aging car. As the car ages, depreciation slows — but maintenance grows faster.

Replace cost per month: new car loan payment (flat for the loan term, then zero) plus new-car monthly depreciation (brutal in year 1 at ~$670/mo on a $40k car) plus HYSA opportunity cost on the capital deployed (down payment + equity from selling).

The crossover point is when keep cost per month first equals or exceeds replace cost per month. Before that: keep wins. After that: replace wins on a per-month basis. The cumulative chart shows the total cost difference across the full analysis horizon.

You might also need

New vs Used Car

Once you've decided to replace, compare whether to buy new or used

Car True Cost of Ownership

Full 5-year TCO breakdown for your new car: insurance, fuel, maintenance, registration

Auto Loan Early Payoff

See how extra payments shrink your new car loan faster

Learn more

→ When to Trade In Your Car: The Math Behind the Decision

Frequently Asked Questions

Why does a new car depreciate so much in year one?
The moment a new car leaves the lot it's no longer 'new,' and buyers discount accordingly. For a mainstream $40,000 vehicle, that year-one hit is roughly $8,000 — about $670 per month. That's the hidden cost most people don't factor in when comparing 'I could buy a new car for $712/mo' against 'my old car only needs $300/mo in repairs.' The new car's depreciation alone nearly matches the difference.
How does maintenance cost escalate on old cars?
A car's repair costs aren't linear — they compound as systems age together. A 7-year-old car averaging $250/mo might hit $350/mo at year 9 and $500/mo by year 11. The calculator uses an annual growth rate (default 10%) to model this escalation. High-mileage vehicles (100k+) get an automatic 1.25× multiplier because wear accelerates disproportionately past the 100k mark.
What is the 'opportunity cost' of replacing my car?
When you replace, you deploy capital: your down payment plus the equity from selling your current car. That money could instead earn 4–5% APY in a high-yield savings account. The calculator adds this foregone interest to the replace-side cost each month, making the comparison fair. On a $15k equity + $4k down, that's roughly $78/mo in lost HYSA interest at 4.5% APY.
What does 'crossover month' mean?
The crossover month is when your current car's monthly cost (maintenance + depreciation) first equals or exceeds the new car's monthly cost (loan payment + depreciation + opportunity cost). Before that month, keeping is cheaper. After it, replacing is cheaper on a per-month basis. The cumulative chart shows when total spending over the whole horizon flips.
When is a new car worth it even if it costs more per month?
Per-month cost isn't the whole story. A new car brings warranty coverage (typically 3yr/36k bumper-to-bumper, 5yr/60k powertrain), lower probability of a catastrophic repair, and full remaining asset life. If your current car has been unreliable or is approaching major scheduled maintenance (timing belt, transmission service), the risk premium on keeping it may outweigh what the numbers say.