When to Drop Collision & Comprehensive Coverage Calculator
Decide whether collision and comprehensive insurance still pays on an older car: premium versus the car’s value minus the deductible, both versions of the 10% rule, break-even claim probability, expected value at your accident risk, comprehensive-only and higher-deductible options, and a year-by-year view of what banking the premium would build.
How it works
Max payout = car value − deductible; premium ÷ value > 10% suggests dropping (stricter version: (premium + deductible) ÷ value > 10%); break-even claim probability = premium ÷ max payout; expected value = P(total loss) × max payout + P(repair claim) × (repair − deductible) − premium; higher deductible pays if P(claim) < premium saving ÷ extra deductible; banked fund = last year’s fund × (1 + interest) + premium
Collision and comprehensive cover repairs or the car’s actual cash value, but never more than that value less your deductible — so as a car ages the most the insurer can ever pay shrinks while the premium barely falls. The classic test is the 10% rule: once a year’s premium exceeds a tenth of the car’s value, the coverage costs more than its expected worth for a typical driver. Some insurers use a stricter version that adds the deductible to the premium before comparing. The sharper test is the break-even claim probability: divide the premium by the maximum payout and ask whether you really total or lose the car that often; add a chance of smaller repair claims under More options for a fuller expected value. Collision is usually the larger part of the bill, so a common middle path is dropping collision but keeping comprehensive, which covers theft, hail, fire, flood and animal strikes — enter the two premiums separately for exact figures, or the calculator estimates the comprehensive share. The projection table shows how the picture changes as the car loses value each year and what the premium would add up to if you banked it instead, including the year the fund could replace the car. The decision also depends on whether you could replace the car from savings tomorrow and whether a lender requires the coverage.
Worked example
A car worth $6,500 with $780 a year of collision and comprehensive at a $500 deductible: premiums are 12% of value and the biggest possible payout is $6,000 — 7.7 years of premiums. Adding the deductible gives $1,280, or 19.7% of value. Coverage only pays if you total the car more than 13% of years; at a 6% risk its expected value is −$420 a year. With $8,000 in savings the sensible move is to drop collision — comprehensive alone would cost about $211 a year — or at least raise the deductible to $1,000 and pocket $160 a year. Banking the $780 at 4% builds $4,225 in five years, when the car is worth about $2,884, and is enough to replace the car in year 5.
Sources: CarInsurance.com — When to drop comprehensive and collision (average premiums by state, 2026) · Insurance Information Institute — Facts + Statistics: Auto insurance
Frequently asked questions
What is the 10% rule for dropping full coverage?
When a year of collision and comprehensive costs more than 10% of the car’s market value, you are paying a lot for a payout that is capped at that value minus the deductible. A stricter version adds the deductible to the premium first. Both are shown, but treat them as prompts: whether you could replace the car from savings matters as much.
Should I drop collision but keep comprehensive?
Often, yes, on an older paid-off car. Comprehensive is usually the cheaper part — about a quarter of the combined price nationally — and covers events you cannot avoid by careful driving, such as theft, hail, floods and hitting a deer. Ask your insurer whether it sells comprehensive on its own; most do.
Does dropping collision affect liability coverage?
No — liability, medical/PIP and uninsured-motorist cover are separate and legally required; collision and comprehensive only cover your own car.
What if someone else hits me?
Their liability insurance pays for your car regardless of your collision coverage; collision matters for at-fault, single-vehicle and hit-and-run damage (uninsured-motorist property damage can fill some of that gap).
What chance of a total loss should I use?
For most drivers it is a few percent a year. Use more for a long daily commute, an area with frequent car theft or hail, or a teenage driver. The break-even figure tells you how high it would have to be for the coverage to pay off on average.
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Educational comparison, not insurance or financial advice. Plan documents, state rules and your own risk tolerance govern the decision; verify figures with the insurer or a licensed agent.