Automotive Financial Calculators & Decision Engines
Institutional-grade utilities designed to audit car dealer quotes, verify interstate sales tax reciprocity, amortize complex vehicle loans, and model multi-year true cost of ownership.
Out-of-State Car Purchase Sales Tax & DMV Reciprocity
Calculate exact sales tax owed across state lines, foreign dealer credit offsets, drive-out exemptions (CDTFA § 6201), trade-in deductions, and temporary in-transit permit requirements.
- Audit Metric: Bilateral state reciprocity matrix
- Input Levers: Purchase State, Home State, Price, Trade-In
- Data Foundation: Audited 2026 State DOR statutes
Trade-In Tax Savings by State
Determine whether your state reduces sales tax when trading in a vehicle. Audits full statutory credit states, statutory trade caps (MI, SC, NC), and zero-credit jurisdictions (CA, VA, DC, HI).
- Audit Metric: Net taxable transaction delta
- Input Levers: Home State, Vehicle Price, Trade Allowance
- Data Foundation: State Administrative Code citations
Auto Loan Decision & Risk Engine
Look past the monthly payment. Scores loan structures on a 0–100 ownership-risk index evaluating loan-to-value depreciation curves, underwater months, and 20/4/10 affordability rules.
- Audit Metric: Months underwater & true interest burden
- Input Levers: Loan APR, Term, Down Payment, Vehicle Value
- Data Foundation: AAA Your Driving Costs 2025 benchmarks
Electric vs Gas 5-Year True Cost of Ownership
Compare multi-year ownership economics across Sedans, Compact SUVs, and Medium SUVs. Models depreciation shock, home vs public charging rates, maintenance deltas, and holding-period breakeven.
- Audit Metric: All-in cents-per-mile cost delta
- Input Levers: Segment, Annual Miles, Charging Mix, Gas $/gal
- Data Foundation: AAA, DOE & iSeeCars 5-year studies
Dealer Documentation Fee Statutory Limit Checker
Audit dealership administrative fees against statutory state caps. Identifies mandatory ceiling states (CA $85, NY $175, TX $225) versus uncapped dealer markup jurisdictions (FL, CO, NC).
- Audit Metric: Statutory fee ceiling vs market average
- Input Levers: Purchase State, Proposed Dealer Fee
- Data Foundation: Audited 2026 DMV regulations & statutes
EV Battery Health & Residual Depreciation Calculator
Model State-of-Health (SoH) battery degradation curves based on calendar age, cycle depth, DC fast-charging ratio, and ambient thermal zone to forecast real-world EV resale value.
- Audit Metric: Battery degradation penalty & range retention
- Input Levers: EV Model, Age, Mileage, Fast-Charge %, Climate
- Data Foundation: Geotab real-world telemetry & EPA cycle data
Used EV Tax Credit Eligibility Validator (IRC § 25E)
Verify statutory compliance for up to $4,000 in federal clean vehicle credits. Checks the statutory $25,000 sales price cap, 2-year model vintage lag, buyer MAGI ceilings, and dealer POS transfer rules.
- Audit Metric: Dollar-for-dollar POS tax credit eligibility
- Input Levers: Vehicle Year, Price, Filing Status, Modified AGI
- Data Foundation: 26 U.S. Code § 25E & IRS Publication 5866-A
Car Repair vs. Sell Financial Breakeven Calculator
Faced with a major repair quote? Compares repairing your vehicle versus selling and buying a replacement. Analyzes post-repair value retention, replacement depreciation, and monthly financial breakeven.
- Audit Metric: Months to recapture repair expenditure
- Input Levers: Repair Cost, Vehicle Value, Replacement Price
- Data Foundation: Actuarial vehicle longevity & residual curves
Auto Loan Refinance Savings & Breakeven Engine
Calculate exact net interest savings from refinancing high-interest dealer loans. Factors in origination fees, transfer costs, and remaining amortization schedules to compute true payback months.
- Audit Metric: Net lifetime interest savings & monthly payment delta
- Input Levers: Current Balance, Current APR, New APR, New Term
- Data Foundation: Closed-form monthly amortization formulas
Car Lease vs. Buy Financial Breakeven Calculator
Compare all-in net cash outlay between 36-month leasing and loan financing. Incorporates money factor interest, residual value targets, sales tax treatment, and post-term vehicle equity.
- Audit Metric: Net financial advantage by holding duration
- Input Levers: MSRP, Negotiated Price, Money Factor, Residual %
- Data Foundation: Institutional captive finance lease math
Vehicle Depreciation & Optimal Holding Period Engine
Model multi-year vehicle depreciation curves across Sedans, SUVs, Trucks, and Luxury segments. Identifies the steep year-one drop and pinpoints the optimal financial window to sell or trade in.
- Audit Metric: Annual value retention curve & cents-per-mile decay
- Input Levers: Vehicle Class, Initial Purchase Price, Annual Miles
- Data Foundation: iSeeCars, BLS automotive CPI & AAA retention data