Repair or Replace Car Calculator
Quick answer: A common rule of thumb is the 50% rule: if one repair costs more than half of your car's current market value, replacement is worth serious consideration. The more complete comparison is annualized cost — divide the repair by the extra years it buys and compare with the replacement's price divided by its expected years of service. This calculator shows both lenses, plus 5-year totals. All figures are estimates, not financial advice.
This repair or replace car calculator helps you decide between fixing your current car and buying a replacement. Enter the repair estimate, your car's market value, and how many more years each option would last — the calculator checks the repair against the 50% rule, compares annualized costs, and totals both options over 5 years.
Enter your numbers
Your results
| 50% rule verdict | — |
| Annualized repair cost | — |
| Annualized replacement cost | — |
| Annual saving with cheaper option | — |
| 5-year repair total | — |
| 5-year replacement total | — |
Estimates only, not financial advice. Both options assume even cost spread per year of use.
How to use this calculator
Get a written repair estimate and an honest read on your car's current resale value, then estimate how many extra years the repair would keep the car running. For the replacement, enter the out-the-door price of the car you would actually buy and how long you would keep it.
Read the 50% rule verdict as a first filter, then weigh the annualized comparison — the two often disagree, and that disagreement is the point of showing both.
How it works
The 50% rule divides the repair estimate by the car's market value: at or above 50%, the rule says consider replacing. The annualized view divides the repair by the extra years it buys and the replacement price by its expected years, comparing the two per-year costs. Five-year totals multiply each annualized figure by five. This is an estimate: it ignores financing interest, insurance changes, fuel economy differences, and breakdown risk.
Worked example
A $3,500 repair on a car worth $6,000 is 58.3% of its value — above the 50% rule, so the rule says consider replacing. Annualized: $3,500 ÷ 3 years = $1,166.67 per year for the repair versus $18,000 ÷ 10 years = $1,800 per year for the replacement — repairing is cheaper per year by $633.33 in this scenario. Five-year totals: $1,166.67 × 5 = $5,833.33 (repair) versus $1,800 × 5 = $9,000 (replacement). The two lenses disagree here, which is exactly why the calculator shows both.
Reference data
| Repair cost vs market value | Rule-of-thumb reading |
|---|---|
| Repair ≤ 50% of value | Repair often reasonable — rule of thumb |
| Repair > 50% of value | Consider replacing — rule of thumb |
Source: derived from the widely cited 50%-of-value rule of thumb (not a published standard; shown as a rule of thumb, not financial advice). No external 2026 data table applies to this tool.
Method & sources
Formulas: repairPct = repair ÷ marketValue × 100. Annualized repair = repair ÷ extraYears; annualized replacement = replacementPrice ÷ expectedYears. Five-year total = annualized figure × 5.
- The 50% rule is a rule of thumb derived from common automotive-ownership guidance, not a published regulation or insurer formula.
- All inputs and results are estimates; this page is not financial advice.
Frequently asked questions
What is the 50% rule for car repairs?
The 50% rule is a rule of thumb: when a single repair costs more than 50% of the car's current market value, many owners start shopping for a replacement instead. It is not a law or an insurer's formula — just a quick filter — so the annualized comparison below is the more complete view.
What does the annualized cost comparison miss?
Reliability and safety. A car can look cheap per year on paper and still leave you stranded or fail inspection. The annualized view also ignores loan interest, insurance changes, fuel economy differences, and resale value — fold those into the replacement price and expected years if they matter to you.
Should I compare against a new or used replacement car?
Either, as long as you use realistic numbers: enter the out-the-door price of the replacement you would actually buy (new or used) and the years you realistically expect to keep it. Run the calculator twice — once with a new-car price and once with a used-car price — to see how much the answer shifts.