Build a coverage-review worksheet from limits you are considering and losses you want to test. The calculator shows how per-person and per-accident liability limits interact, checks separate property and medical scenarios, and illustrates deductible exposure for physical damage to your vehicle. It does not determine required coverage or calculate a premium.
Insurance calculator Content updated 2026-08-16Calculations run privately in your browser
Cindy Zhang and Heather Kincaid co-authored the plain-language limit arithmetic, input guidance, worked scenario, result interpretation, limitations, and links to NAIC and Consumer Financial Protection Bureau resources. This is an editorial authorship scope, not a claim of actuarial, insurance-agent, producer, adjuster, underwriting, claims, lending, legal, or state-regulatory review.
The byline does not claim professional credentials, trade, finance, insurance, actuarial, underwriting, or claims experience, licensed review, or independent professional review for either author.
Enter coverage limits and test scenarios
Example values are prefilled
How to use this auto coverage calculator
Compare entered auto insurance limits and deductibles with transparent injury, property-damage, medical-payment, collision, and comprehensive loss scenarios.
Formula
Modeled injury loss = loss per person × injured people. The bodily-injury liability test and a separate uninsured/underinsured-motorist test each use min(modeled loss, per-person limit for that coverage × injured people, per-accident limit for that coverage); each gap is the remainder, without assuming the two coverages respond together. Property and medical gaps compare their scenarios with their separate entered limits. When a physical-damage coverage is marked included, its example caps loss at entered vehicle value and subtracts its deductible. When marked not included, the modeled covered amount is $0, the deductible is ignored, and the full entered loss remains cash exposure. Collision and comprehensive are compared separately with emergency savings.
Quick example
Example: With $100,000 per person and $300,000 per accident, three modeled injuries of $125,000 total $375,000. No more than $300,000 fits within both entered bodily-injury limits, leaving a $75,000 arithmetic gap before policy terms; the same injury amounts are tested separately against the entered UM/UIM limits. With collision marked included, a separate $18,000 collision scenario and $1,000 deductible produce $17,000 after the deductible. If collision is marked not included, the deductible is ignored, the modeled covered amount is $0, and all $18,000 remains cash exposure.
Accuracy and limitations
The worksheet performs limit and deductible arithmetic only. It does not decide fault; value bodily injury; include legal defense, supplementary payments, offsets, stacking, subrogation, depreciation, taxes, fees, loan or lease payoff, GAP coverage, or policy exclusions; establish actual cash value; or predict a claim payment. State financial-responsibility, no-fault, PIP, medical-payments, and uninsured-motorist rules change. Obtain current requirements from the state insurance department and rely on the policy and finance or lease contract for binding terms.
Sources and formula references
NAIC: Auto Insurance consumer guide — Official consumer explanations of liability, uninsured-motorist, collision, comprehensive, deductibles, and state-system differences
NAIC: Auto Insurance Shopping Tool — Official coverage checklist explaining state minimum variation, liability exposure, physical-damage coverage, loans, and leases
Use a declarations page or itemized quote and distinguish each per-person, per-accident, and property limit. A shorthand such as 100/300/100 usually represents three different caps; it does not create one interchangeable $500,000 pool.
Verify the state framework
Auto financial-responsibility, tort or no-fault systems, PIP, medical payments, and uninsured or underinsured motorist rules vary by jurisdiction and can change. This tool deliberately contains no state-minimum lookup. Use the linked NAIC directory to reach the current state regulator.
Separate your vehicle from third-party liability
Property damage liability concerns property you damage that belongs to someone else. Collision and comprehensive concern physical damage to the insured vehicle. Mark each one included only when it appears in the candidate policy; when it is not included, the worksheet ignores that deductible and leaves the full scenario as cash exposure.
Use scenarios as stress tests
Enter losses that help you see how the arithmetic behaves, then vary one input at a time. The numbers do not assign fault or predict medical bills, repair costs, settlements, judgments, or insurer payments.
Check financing requirements
If the vehicle is financed or leased, read the contract for collision, comprehensive, deductible, and loss-payee requirements. State-required liability coverage and a creditor's collateral requirements answer different questions.
How the calculation works
Build the injury scenario
Multiply the entered loss per injured person by the number of injured people to obtain a single hypothetical bodily-injury total.
Apply each pair of split injury limits
For bodily-injury liability, calculate the per-person limit times the number of people, then take the lowest of that product, the per-accident limit, and the modeled total. Reuse the entered injury amounts only as a separate alternative UM/UIM split-limit test. The two coverages are not added and the arithmetic does not predict entitlement under either one.
Keep property and medical comparisons separate
Compare third-party property damage only with the entered property-damage liability limit and the medical scenario only with the entered medical-payments-style limit. The tool does not move unused limits between coverages.
Branch on physical-damage coverage
When collision or comprehensive is marked included, cap that alternative loss at the entered vehicle value and subtract its deductible without allowing a negative result. When it is marked not included, ignore its deductible, set its modeled covered amount to $0, and leave the full entered loss as cash exposure.
Review household cash exposure
Compare each deductible or modeled uncovered amount with the same emergency-savings input one scenario at a time. Do not add collision and comprehensive examples as though both happen together.
Worked calculation: Consider candidate limits of $100,000 bodily injury per person, $300,000 bodily injury per accident, $100,000 property damage, and $5,000 medical payments per person. Test three bodily injuries at $125,000 each, $80,000 of third-party property damage, $12,000 of first-party medical expense, and—separately—$18,000 of collision damage to a $30,000 vehicle. For the first branch, collision is marked included with a $1,000 deductible.
Multiply $125,000 by three injured people to obtain a $375,000 bodily-injury scenario.
The per-person limits across three people total $300,000, and the per-accident limit is also $300,000. The lowest of $375,000, $300,000, and $300,000 is $300,000 within the entered limits.
Subtract $300,000 from $375,000 to show a $75,000 scenario gap before policy terms, fault, legal defense, claims adjustment, or other insurance.
The $80,000 property scenario is $20,000 below the separate $100,000 property-damage limit. The $12,000 medical scenario is $7,000 above the separate $5,000 entered medical-payments limit.
With collision marked included, the $18,000 loss is below the entered $30,000 vehicle value. Subtract the $1,000 deductible to show $17,000 after deductible and at least $1,000 of household cash exposure in this simplified branch.
Change collision to Not included: the worksheet ignores the $1,000 deductible, displays a $0 modeled covered amount, and leaves the full $18,000 entered loss as cash exposure.
Result: The example reveals a $75,000 bodily-injury scenario gap and a $7,000 medical scenario gap, while the property test remains within its entered limit. The physical-damage branch changes from $17,000 after deductible when collision is included to $0 when it is not included. Those are arithmetic observations—not a recommendation or estimates of an actual claim.
Next step: Replace the example limits with identically structured quotes, verify current state and finance-contract requirements, review exclusions and endorsements, and ask a licensed insurer or producer to explain any remaining scenario gaps.
Interpret the result
Within entered limits is not promised payment
The displayed amount only fits the numerical caps entered. Coverage, exclusions, fault, damages, defense handling, other insurance, and claims adjustment determine whether and how a real policy responds.
A gap is a planning signal
A positive gap means the scenario exceeds the selected numerical limit in this worksheet. It does not forecast personal liability, settlement value, or the amount a court or insurer would determine.
UM/UIM is a separate alternative test
The worksheet reuses the entered injury amounts to test the separate UM/UIM per-person and per-accident limits arithmetically. It does not add liability and UM/UIM coverage or predict entitlement. Definitions, stacking, offsets, covered people, rejection rules, and availability can be state- and policy-specific.
Vehicle-value and no-coverage branches are simplified
For an included physical-damage coverage, the model uses the value you entered; it does not establish actual cash value or decide whether a vehicle is repaired or totaled. When the coverage is not included, it ignores the deductible and leaves the full scenario as cash exposure. A remaining loan balance is not the same as vehicle value.
Mileage and passengers are prompts
These context fields help organize questions for a licensed insurer or producer. They do not change the calculated gaps, estimate risk classification, or calculate a price.
Common mistakes to avoid
Treating a state's required minimum as a personalized coverage recommendation or assuming the calculator knows current state law.
Adding per-person and per-accident liability limits together instead of recognizing the per-accident aggregate cap.
Using property damage liability as though it pays to repair the insured vehicle.
Leaving collision or comprehensive marked included when the candidate policy does not contain it, or treating a deductible as though it creates coverage.
Assuming collision, comprehensive, PIP, medical payments, and uninsured-motorist coverage exist or work the same in every state.
Comparing premiums from quotes that use different limits, deductibles, drivers, vehicles, endorsements, or effective dates.
Assuming a vehicle loan balance determines a total-loss valuation or that GAP is included automatically.
Decision checklist
Confirm current legal requirements with the state insurance department and retain the dated source.
Ask for quotes with identical drivers, vehicles, use, limits, deductibles, endorsements, and effective dates.
Read the declarations, definitions, exclusions, conditions, and endorsements; mark collision and comprehensive included only when shown rather than relying on a 'full coverage' label.
Check loan or lease requirements and distinguish physical-damage insurance, force-placed insurance, and optional GAP products.
Test a multi-person injury, expensive third-party property loss, and one physical-damage deductible separately.
Ask a licensed producer or insurer to explain in writing how state-specific PIP, medical, and uninsured-motorist provisions apply.
Frequently asked questions
Does this calculator tell me my state's minimum auto insurance limits?
No. Requirements and coverage systems vary and can change. Use the NAIC state insurance department directory to find the current regulator, then confirm requirements for the vehicle's registration and use.
Is this a car insurance quote or premium calculator?
No. It performs scenario-to-limit arithmetic and sends no application to an insurer. It does not use driver, credit-based insurance score, garaging, claims, vehicle, underwriting, rating, discount, or territory data needed for a quote.
What do per-person and per-accident bodily injury limits mean here?
The model first caps each modeled person's loss at the entered per-person limit, then caps the combined event at the entered per-accident limit. Actual wording and claim treatment come from the policy.
Does property damage liability cover my car?
No. In this worksheet, property damage liability is compared with damage to other people's property. Collision and comprehensive scenarios address the entered value of your vehicle and their separate deductibles.
Does a financed or leased car need collision and comprehensive coverage?
The legal and contractual questions are separate. Finance and lease contracts commonly impose physical-damage requirements, but you must read your contract and quote. The calculator does not determine compliance.
Why doesn't the estimator calculate one total amount of auto coverage?
The coverages protect different people or property, use separate limits and deductibles, and are not normally one interchangeable fund. A single sum would conceal those boundaries.
What is the difference between medical payments and PIP?
They can cover different expenses, people, and benefits, and PIP or no-fault rules are jurisdiction-specific. Enter only the limit shown in your document and ask the state regulator or licensed producer how the coverage works.
What happens when collision or comprehensive is marked Not included?
The worksheet ignores that coverage's deductible, sets its modeled covered amount to $0, and treats the full entered loss as cash exposure. This is still only a planning scenario and does not interpret another policy or source of recovery.
Does the physical-damage result predict a total-loss check?
No. When coverage is marked included, it uses your value estimate and subtracts a deductible for a simple scenario. It does not establish actual cash value, repairability, taxes, fees, salvage, depreciation, loan payoff, or policy coverage.
Are uninsured and underinsured motorist limits included in the gap formula?
Yes, as a separate alternative arithmetic test. The worksheet reuses the entered injury amounts against the UM/UIM per-person and per-accident limits; it does not add liability and UM/UIM coverage or predict entitlement. State rules and policy terms control.
