Auto Insurance Cost Calculator
Collision verdict, liability tier, and umbrella advice.
What it does
Collision coverage protects the lender first and the driver second, and on cheap cars its premium can eclipse any payout. The 10% rule settles it: premiums above a tenth of value buy too little protection.
The tool above takes car value, yearly collision premium, and asset tier. It returns the keep or drop verdict, a liability tier, and umbrella guidance.
The default $18,000 car at $900 runs 5%, so keep collision with 100/300/100 and a $1M umbrella thought. The flipped case of $4,000 at $800 hits 20%, so drop it.
Insurance Information Institute teaching repeats the 10% cutoff with 100/300/100 as the adequate middle tier. NAIC shopping guidance adds the comparison method: equal coverage, equal deductibles, checked insurer strength.
Liability follows assets because lawsuits do. Minimums shield paychecks poorly once savings, equity, and future wages enter the picture.
How to use
- Type the car market value.
- Type the yearly collision premium.
- Pick the asset tier.
- Read keep or drop first.
- Read liability beside it.
- Read umbrella advice last.
Formula
- value
- Market value of the insured car.
- premium
- Yearly collision plus glass premium.
- assets
- Low, mid, or high household assets.
Insurance Information Institute guidance carries the 10% collision rule with 100/300/100 as the widely quoted adequate tier. NAIC consumer guidance frames shopping by coverage, deductible, and insurer strength the same way. Tiers here simplify real underwriting, which also weighs record, miles, and territory.
Worked example
Example: $18,000 car at $900
Defaults: $18,000 car, $900 premium, mid assets.
- Car: $18,000 value with $900 yearly collision premium.
- Share: 900 / 18000 = 5% of value.
- Rule: over 10% means drop, so keep this one.
- Assets mid tier maps to 100/300/100 liability.
- Umbrella: mid tier suggests considering $1M.
- Tool shows Keep collision: 5% of value, 100/300/100, Consider a $1M umbrella.
Reference table
| Car and premium | Share | Verdict |
|---|---|---|
| $18,000 at $900 | 5% | Keep, 100/300/100 |
| $4,000 at $800 | 20% | Drop, 50/100/50 |
| $30,000 at $1,500 | 5% | Keep, 250/500/100 |
| Paid off, liability only | n/a | Price UM/UIM match |
Limits
- Guidance math, not a filed quote.
- Territory and record move real prices.
- Lender rules override drop advice.
- State minimums vary widely.
Common mistakes
- Insuring a $3,000 car fully forever.
- Buying minimums with a house at stake.
- Skipping UM/UIM matching.
- Raising deductibles past emergency funds.
- Comparing quotes at unequal coverage.
Try it yourself
Quick checks. Answers sit tucked under each question.
$4,000 car, $800 premium, low assets?
20% of value: Drop collision: 20% of value, 50/100/50, no umbrella.
$30,000 car, $1,500 premium, high assets?
5% of value: keep, 250/500/100, carry a $1M+ umbrella.
$0 premium on any car?
0% of value: keep, since the coverage costs nothing here.
Questions
When do I drop collision?
Drop collision and glass cover when the yearly premium tops 10% of the car value. A $4,000 car at $800 fails at 20%.
What do 100/300/100 mean?
Bodily injury per person / per crash / property damage, in thousands. 100/300/100 is the common advice for mid assets.
Umbrella policy?
Extra million plus liability above auto and home limits, for households with much to protect.
Which deductible?
$500 to $1,000 deductibles trade premium for risk; $250 suits tight budgets with lender rules in mind.
Loan or lease?
Lenders demand full coverage to loan end. Paid off cars free the choice.
Beyond collision?
At fault, underinsured, and uninsured gaps need matching liability and UM/UIM limits, not minimums alone.