Auto Insurance Premium Calculator

Quotes start from two objects: customer, with age and the drivingHistory incident counts, and policy, carrying coverageAmount, coverageType, deductible, vehicleAge, and vehicleType. These are the only fields the rater reads.

Driver pricing crosses customer.age bands against a derived Total Incidents column, customer.drivingHistory.accidentsLast3Years plus violationsLast3Years, under a first hit policy. Drivers under 25 with more than 1 incident take the worst ageRiskFactor of 1.5 and a 'high' category, [25..65] drivers with zero incidents rate 1.0 and 'low', and over-65 drivers land at 1.1 or 1.3 depending on whether they have any incidents at all.

Collapsing accidents and violations into one incident count is a simplification of the surcharge points real raters use, but the shape matches loss experience: youthful operators and incident frequency are the two strongest predictors of auto claims, which is why no under-25 row rates better than 1.3. The mild senior loading reflects the gradual frequency uptick past retirement age rather than any hard cutoff.

A flat rate of 5.5 per thousand anchors the price: coverageAmountInThousands divides policy.coverageAmount by 1000 and basePremium multiplies the two, so the sample 300000 policy starts at 1650 before any risk factors apply. Rate-per-thousand is the standard way carriers express base rates, which keeps the starting number legible to underwriters.

Each vehicle row pairs policy.vehicleType with a policy.vehicleAge band: sedans run from 0.9 under 3 years to 1.1 past 7, an 'suv' runs 1.1 to 1.3, and 'sports' cars climb from 1.5 to 1.8 over the same age bands. A blank catch-all row assigns 1.2 to any unrecognized type, so the table always prices.

Sports cars carrying roughly double the sedan factor tracks how symbol-based vehicle rating penalizes performance vehicles on both claim frequency and severity. Loading older vehicles more within each type is a sensible choice for this template: aging cars lack current safety and anti-theft equipment, even though their lower replacement cost cuts the other way on physical damage.

The last table maps policy.coverageType against deductible bands with a first hit policy: 'basic' cover with a deductible above 1000 earns the cheapest coverageFactor of 0.8, 'comprehensive' with a deductible under 500 tops out at 1.3, and a blank fallback row emits a neutral 1.0. Its outputs also declare the premium field the graph returns.

Deductible credits of this shape are ordinary retention pricing: every dollar the insured keeps reduces expected paid losses and suppresses small-claim frequency, so within each coverage type a higher deductible always moves the factor down. The gap between 'basic' and 'comprehensive' rows reflects that comprehensive adds first-party physical damage perils on top of liability, which is genuinely more exposure, not just a richer tier name.