Methodology

Philosophy

Every calculator on GetAutoCalcs uses deterministic, well-documented formulas. We don't use proprietary "models" or opaque machine-learning estimates. The math is simple enough that you could verify it by hand — and we show you the formulas so you can.

Standard loan math (PMT formula)

Monthly Payment = P × [r(1+r)^n] / [(1+r)^n − 1]

Where P is principal, r is the monthly interest rate (APR/12), and n is the number of monthly payments.

Lease math

We use the standard lease formula: monthly = depreciation + finance, where depreciation is (cap cost − residual) / term and finance is (cap cost + residual) × money factor.

OBBBA EV loan interest deduction

The One Big Beautiful Bill Act (Public Law 119-21, July 2025) created an above-the-line deduction for interest on qualifying new vehicle loans. Up to $10,000/year is deductible, subject to MAGI phase-out ($100K–$150K single, $200K–$250K MFJ; reduced $200 per $1,000 over the threshold). Vehicle must be new, personally used, under 14,000 lbs GVWR, with final assembly in the US. See our /ev-loan-interest-deduction-calculator/ page for details.

Section 30C home charger credit

30% of equipment and installation cost, capped at $1,000 for residential installations. Property must be placed in service by June 30, 2026 and located in a qualifying low-income or non-urban census tract.

EV charging cost

cost per mile = (1 / efficiency_mi_per_kWh) × (1 + charging_loss) × $/kWh

Default charging loss is 10% (covers Level 2 AC-DC conversion plus battery heating/cooling).

Depreciation

We use a conventional "20/15/15/15/15" curve: ~20% drop in year one, ~12% per year for years 2–5, and ~8% per year thereafter. Individual models vary widely — use our depreciation calculator with care.

Data sources

• Federal Reserve G.19 — consumer credit rates
• EIA — electricity prices (residential monthly)
• DOE Alternative Fuels Data Center — state incentives and EV tax credits
• IRS — federal tax rules
• AAA — vehicle maintenance and insurance averages