Repair vs Replace Decision Calculator
ROI of repair vs replacement.
About this calculator
This calculator scores whether to repair or replace a vehicle using the classic "50% rule" -- if the estimated Repair cost exceeds half the vehicle's current value, conventional wisdom favors replacing -- alongside a broader 0-100 Replace score that also weighs vehicle age, current mileage, and estimated years of life remaining after the repair (based on driving 200,000 miles as a typical usable lifespan). The 3-year cost comparison is the calculator's most concrete number: it adds the Repair cost to an age-bracketed annual maintenance estimate and compares that total against 36 months of the payment you'd make on a replacement plus a flat maintenance estimate for a newer vehicle.
Repair cost dominates that comparison because it can range from nothing to $50,000, dwarfing the few-thousand-dollar swing that age-bracketed maintenance produces on its own. What the calculator does not weigh: financing costs or interest on a replacement loan, sales tax and fees, the trade-in or resale value you'd recover from the current vehicle, whether the needed repair is safety-critical versus cosmetic, or your actual maintenance history beyond a flat estimate keyed only to age.
Inputs
Results
Replace score (0-100)
35
How to Use This Calculator
- Enter Current vehicle value ($), Estimated repair cost ($), and Vehicle age (years).
- Set Current mileage, Annual miles driven, and Monthly payment if replaced ($).
- Review the Replace score (0-100) result.
- Use Repair as % of value (%) and 50% rule threshold ($) ($) to inform your decision.
How the result changes with Current vehicle value ($)
| Current vehicle value ($) | Replace score (0-100) |
|---|---|
| 4,000 | 45 |
| 6,000 | 35 |
| 12,000 | 25 |
| 20,000 | 25 |
What each input means
- Current vehicle value ($)
- Fair market value (check KBB or Edmunds).
- Estimated repair cost ($)
- Total cost of needed repairs.
- Vehicle age (years)
- How old the vehicle is.
- Current mileage
- Current odometer reading.
- Annual miles driven
- How many miles you drive per year.
- Monthly payment if replaced ($)
- Expected monthly payment on a replacement vehicle.
What each result means
- Replace score (0-100)
- Higher = stronger case to replace. Below 30 = repair, 30-60 = borderline, above 60 = replace.
- Repair as % of value
- Repair cost relative to vehicle value. Over 50% generally favors replacement.
- 50% rule threshold ($)
- If repair exceeds this, the 50% rule suggests replacing.
- Est. years remaining
- Estimated usable life remaining after repair based on mileage.
- 3-year cost to keep
- Repair cost plus estimated maintenance over 3 years.
- 3-year cost to replace
- Payments plus maintenance on a replacement vehicle over 3 years.
- 3-year savings if keeping
- Positive = keeping saves money, negative = replacing is cheaper.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersCurrent vehicle value ($) = 8000, Estimated repair cost ($) = 2500, Vehicle age (years) = 10, Current mileage = 120000 = 6 input(s) provided
- Calculate Replace scoreReplace score35 = 35
- Calculate Repair as % of valueRepair as % of value = repairCost / vehicleValue31.3 = 31.3%
- Calculate 50% rule threshold50% rule threshold = vehicleValue * 0.54000 = $4,000
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Which inputs actually move the 3-year cost to keep?
Only two: Repair cost is added dollar-for-dollar, and Vehicle age sets an age-bracketed annual maintenance estimate that's multiplied by three years. Current mileage, Annual miles driven, and Monthly payment if replaced never appear in that formula at all -- a high-mileage car with a cheap repair still shows the same 3-year cost to keep as a low-mileage one with an identical repair cost and age.
Does the Monthly payment if replaced input affect the 50% rule threshold?
No. The 50% rule threshold is simply half of Current vehicle value, so it responds only to that one input -- Monthly payment if replaced, Repair cost, Vehicle age, Current mileage, and Annual miles driven all leave it unchanged. It's a fixed dollar line you compare your Repair cost against, not a moving target.
Why does the Replace score go up as the vehicle gets older, even if the repair itself is minor?
The Replace score adds points for age brackets (over 7, 10, and 15 years) on top of whatever points the repair-to-value ratio and mileage contribute, because an older vehicle is statistically more likely to need another expensive repair soon after this one. That means two vehicles needing an identical $500 repair can land at different Replace scores if their ages differ.
Is a Replace score of 100 supposed to mean replacement is certain?
Not literally -- 100 is simply this calculator's maximum achievable score once every bracket (repair ratio, age, mileage, and years remaining) contributes its highest weight, and the labeled bands are 30 and under favors repair, 30-60 is borderline, and above 60 favors replacing. Treat it as a relative signal built from a few common heuristics, not a certified verdict.
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