Repair or Replace Car Calculator
The repair in front of you, and the car that would replace it
Your result will appear here
Fill in the fields on the left and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- General mathematical model
- Scope and limitations
- Educational estimate only. Confirm the assumptions, current rules, fees, and rounding that apply to your situation before making a decision.
- Source links checked
- Jul 30, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
How to use
- 01
Enter the repair estimate, then what the car is worth once repaired and what it would fetch today unrepaired. Guide values are fine for both; a dealer's as-is offer is better for the second.
- 02
Enter the other repairs and maintenance you expect the car to need next year and how fast you think that figure will rise. Both are your judgment, so start from the shop's list of what is wearing out.
- 03
Describe the replacement: its price, the sales tax and fees on it, the cash you would put down on top of the old car, and the loan rate and term. Experian's Q2 2026 averages were 6.35% on new cars and 11.19% on used.
- 04
Add the replacement's own yearly repairs, how much more it would cost to insure, and the number of years to compare over.
- 05
Read the yearly cost of each path and the table beneath it, then check the rule-of-thumb stat and the repair bill at which replacing would start to win.
Formula
Each path is measured as cost so far = cash spent + the as-is value of the old car given up − the value of what you own at that point, and the yearly figure is the total divided by the years compared. Keeping: the repair bill + the other repairs each year (next year's figure, rising by your growth rate) + the as-is value − the repaired car's value after losing your yearly percentage. Replacing: the cash down + the loan payments + the replacement's yearly repairs + the extra insurance + the as-is value − (the replacement's value − the loan still owed). The loan is the price plus tax and fees, less the as-is value and the cash down; the replacement's value falls each year at the rate implied by the five-year depreciation figure (41.8% on iSeeCars' March 2026 study). The yearly gap is replacing's cost a year less keeping's. The break-even repair bill is the current bill plus the difference between the two totals.
Example
A car needs a $4,200 repair. Repaired it is worth $7,500; as-is it would fetch $3,000. It is expected to need $1,800 of other work next year, rising 10% a year, and to lose 12% of its value a year. The alternative is a $27,000 used car with $2,100 of tax and fees and $2,000 down on top of the old car's value, leaving $24,100 financed at 11.19% over 68 months, a $480 payment, plus $1,490 a year of repairs and $450 a year more insurance. Over five years keeping the car costs $14,231, or $2,846 a year: the $4,200 repair, $10,989 of later repairs and the $3,000 as-is value given up, less the $3,958 it is still worth. Replacing costs $31,481, or $6,296 a year, including $11,286 of depreciation, $8,395 of interest, $7,450 of repairs, $2,250 of insurance and $2,100 of fees. Keeping it saves $3,450 a year, $17,250 in all. The bill is 56% of the repaired value, so the 50% rule says replace, yet the break-even repair bill is $21,450.
Definitions
- As-is value
- What the car would fetch today with the fault unrepaired, as a trade-in or a private sale. Both paths give up this value, so it frames the cost rather than deciding it.
- Cost so far
- Cash spent on a path plus the as-is car given up, less the value of the car you own at that point and any loan still owed on it. It can be negative when a repair adds more value than it costs.
- Break-even repair bill
- The repair bill at which keeping and replacing cost the same over the comparison period, with every other input unchanged.
- 50% rule
- A rule of thumb that says repair a car when the bill is less than half its value. It compares one bill with one value and ignores what a replacement costs to own.
- Depreciation
- The value a car loses while you own it. On a replacement it is usually the largest cost of the switch, and it arrives as a lower resale price rather than as a bill.
Good to know
Why half the car's value is the wrong yardstick
The most repeated advice about an expensive repair is to fix the car if the bill is less than half of what the car is worth, and to replace it otherwise. The rule is easy to apply and sounds prudent, but it compares the wrong two numbers. The value of your car is not what it costs to replace the transportation it provides. Replacing it means buying a different car, and that car brings its own depreciation, its own sales tax and fees, usually a loan with interest, and often a higher insurance bill. None of those appear in the rule. On this page's example, a $4,200 repair on a car worth $7,500 once fixed is 56% of its value, so the rule says replace. Yet the replacement, a $27,000 used car financed at 11.19%, costs $4,806 a year in depreciation, interest, insurance and fees before it needs a single repair of its own. Keeping the old car costs $2,846 a year, including the repair and the further work it is expected to need; replacing it costs $6,296. The rule gets the answer wrong by $3,450 a year. It can also fail in the opposite direction. A $900 bill on a $7,500 car passes the test easily, but if the same car needs a transmission next spring, paying the $900 only delays a larger decision. What matters is the total cost of each path over the years you would keep driving, which is why this page asks for the repairs still to come and not just the bill in front of you. A better quick check than the 50% rule is the break-even repair bill: the bill at which both paths cost the same. In the example it is $21,450, nearly three times the car's value, which shows how far the rule's threshold can sit from the real crossover when the replacement has to be financed.
What replacing actually costs in the first five years
A replacement car's price is not what it costs you, because much of the price comes back when you sell it. What does not come back is the value it loses, the interest on the loan, the tax and fees, and any increase in insurance, and those are what this page charges. Depreciation is usually the largest. iSeeCars' March 2026 study of more than 950,000 five-year-old cars put the average loss over five years at 41.8% of the original price. On the example's $27,000 replacement that is $11,286, although a car bought a few years old usually loses fewer dollars than a new one, because its first owner has already absorbed the steepest part of the curve. For scale, Cox Automotive put the average used-vehicle listing at $27,028 in July 2026. Interest comes next. Experian's State of the Automotive Finance Market for the second quarter of 2026 put the average rate at 6.35% on new cars and 11.19% on used cars, with an average used-car term of about 68 months. Financing $24,100 on those terms is a $480 payment and $8,395 of interest in the first five years, with $3,685 still owed at the end. Credit matters more than almost any other input: the same report's used-car averages ran from 6.29% for super prime borrowers to 21.62% for deep subprime. Sales tax, title, registration and dealer fees are a loss the day you sign, $2,100 in the example. Insurance usually rises with a newer, more valuable car, so get a quote rather than guessing; the example assumes $450 a year more. And a replacement still needs maintenance. AAA's 2025 Your Driving Costs study put maintenance, repair and tires at 11.04 cents a mile for new cars, about $1,490 a year at 13,500 miles. Add it all up and the example replacement costs $6,296 a year before anything goes wrong with it.
Forecasting the repairs an older car still needs
The weak point of any repair-or-replace comparison is the future repair bill on the car you keep, because nobody publishes a forecast for your car. What the evidence does show is the direction. Consumer Reports' analysis of its 2025 Annual Auto Surveys, updated in December 2025, finds that maintenance and repair costs rise as a car ages and can climb steeply once the manufacturer's warranty and any free maintenance period end, and that ten-year costs for the cheapest brands to maintain are about a quarter of those for the most expensive. CarMD's 2026 Vehicle Health Index, built from repair data on more than 39 million vehicles in calendar 2025, put the average check-engine repair at a record $554, up 33% from the year before, with labor costs up 51% and parts up 23%. Its most expensive common repair, a catalytic converter, averaged $1,511. The same report puts the average age of US vehicles at 12.8 years, an all-time high, which is itself evidence that most owners keep repairing. So treat the two repair fields as a range rather than a single number. Start from what a trusted shop says is wearing out: tires, brakes, suspension parts, belts, fluids, and anything flagged while doing this repair. Price those, spread them over the next year or two, and use that as next year's figure. Then run the page at a growth rate of 10% and again at 25% and see whether the answer changes. If keeping the car wins at both, the decision is robust. If it flips, the question is really how long the car's major components will last, and a second opinion on the diagnosis is worth more than any calculator. The break-even repair bill helps here too: if the answer changes only when future repairs become implausibly large, you can repair with confidence.
Sunk costs, safety and the parts no spreadsheet holds
Two mistakes distort this decision more than any arithmetic error. The first is counting money already spent. If you paid $2,000 for a repair last year, that money is gone whichever path you choose now, and it should play no part in deciding whether to pay for the next one. Owners often keep repairing a car because they have already put so much into it, or replace a car out of frustration the week after a big bill. This page deliberately starts from today: the repair in front of you, the car's value now and the costs from here on. The second mistake is treating a car's value as a scorecard. A car worth $3,958 at the end of five years is not a failure if it cost $2,846 a year to drive, and a car worth $15,714 is not a success if it cost $6,296. What decides whether the money was well spent is what each year of driving cost. Some things belong in the decision that no field can hold. Newer cars generally carry more safety equipment. A repaired car can fail in a different system shortly afterward, and a used replacement carries a history of its own, so a pre-purchase inspection matters as much as its price. Time without a car, rentals during repairs and how much you depend on the car for work or family all have real value. The page also leaves out what your down payment could have earned elsewhere, which slightly favors keeping the car. If the numbers are close, those factors should decide. If they are far apart, as in the example where keeping saves $17,250 over five years, it takes a strong safety or reliability reason to override them. Either way, get the diagnosis confirmed and a firm written quote before relying on any comparison.
Frequently asked questions
Should I fix my car or buy another one?
Compare what each path costs a year, not the repair bill against the car's value. On this page's example, a $4,200 repair on a car worth $7,500 once fixed, with $1,800 of further repairs expected next year and rising 10% a year, costs $2,846 a year to keep over five years. Replacing it with a $27,000 used car financed at 11.19% costs $6,296 a year once depreciation, interest, insurance, repairs and fees are counted. Keeping it is $3,450 a year cheaper.
Is the 50% rule for car repairs right?
It is a shortcut, and it often points the wrong way. The rule says repair when the bill is under half the car's value. In the example the bill is 56% of the value, so the rule says replace, while the full comparison says keeping the car saves $3,450 a year. The rule leaves out what the replacement costs to own, $4,806 a year in depreciation, interest, insurance and fees in the example, and it ignores the repairs the old car still needs, which can make even a small bill the wrong call.
Why does the car's value count if I am not selling it?
Because it is money you are holding in the form of a car. Both paths are measured as cash spent plus the as-is car given up, less what you own at the end. Keeping the example car leaves you with a car worth $3,958 after five years; replacing it leaves a car worth $15,714 with $3,685 still owed. Counting both is what stops the comparison from treating a newer car's higher value as free.
How much does the loan add to replacing?
Often more than people expect. Financing $24,100 at 11.19% over 68 months is a $480 payment and $8,395 of interest in the first five years, with $3,685 still owed at the end. Experian's Q2 2026 used-car rates ran from 6.29% for super prime borrowers to 21.62% for deep subprime, so your credit score can move the answer more than the repair bill does.
How much will repairs on an older car keep costing?
Nobody can forecast your car's future bills, which is why they are a field and an assumption here. Consumer Reports' repair and maintenance data, updated December 2025, finds costs rise as a car ages and can climb steeply once warranty and free maintenance periods end. CarMD's 2026 Vehicle Health Index put the average check-engine repair at $554 in 2025, up 33% in a year, and the average US vehicle is now 12.8 years old. A shop's inspection of what is wearing out is the best input you can get.
At what repair cost should I replace the car?
The page answers that directly with the break-even repair bill: the bill at which both paths cost the same over your comparison period, with everything else as entered. In the example it is $21,450, nearly three times the car's value, because the replacement's depreciation and interest are so large. A car facing heavy repairs every year reaches its break-even much sooner, which is why the repairs still to come matter more than the bill in front of you.
What does this calculator leave out?
Things no field can hold: the safety equipment a newer car brings, the chance a repaired car fails somewhere else soon after, the unknown history of a used replacement, and the days without a car while it is in the shop. It also does not charge the cash down payment for what it could have earned elsewhere. Use the result as the money side of the decision, not the whole of it.