Methodology
Every number on MotiveGrid is derived from primary sources and documented assumptions. We show you what goes into each score, where the data comes from, and what we deliberately don't model — because honest limitations build more trust than false precision.
Analysis by the MotiveGrid Engineering Team · reviewed against primary sources
Depreciation
Depreciation is the largest single cost component for most vehicles, yet it's the one most buyers ignore at purchase. We model it as the dollar difference between what you pay and what the vehicle is worth after five years.
Insurance
Insurance is the part of ownership cost that varies most across drivers, so we model the part of it that depends on the vehicle — the contribution you can control by choosing a different car. This is MotiveGrid's own archetype-based model, built in-house and calibrated against MoneyGeek's vehicle-level premium data (national average gap held under 3%).
Fuel & Electricity
Energy cost uses official EPA efficiency ratings and government-reported energy prices. The calculation is structurally identical for gas and electric vehicles — annual miles divided by efficiency, multiplied by energy price — but each powertrain type has its own data inputs and adjustment model.
Maintenance & Repairs
Annual maintenance cost covers scheduled service and unscheduled repairs over the first five years of new-vehicle ownership. EVs carry a structural cost advantage — no oil changes, fewer brake events from regenerative braking, fewer wearing components — and that difference is reflected in the archetype baselines, not assumed at the model level. This is MotiveGrid's own model, calibrated against CarEdge first-5yr cost data.
Tires
Tire replacement is the most mileage-driven operating cost — tires wear out per mile, not per year — so the model is per-segment with an EV uplift, and the calculator scales the baseline with how much you actually drive.
Registration
Annual vehicle registration is one of the most state-variable costs in ownership. Flat-fee states like Arizona look nothing like ad-valorem states like California or Virginia, where what you pay is a fraction of the vehicle's assessed value. The model captures both shapes plus the EV-fee layer most states have added since 2020.
Financing
Financing cost is computed from standard loan amortization using the loan amount, interest rate, and term. The model is transparent — all inputs are visible and adjustable in the calculator.
Federal EV Tax Credit
The federal Clean Vehicle Credit (IRS Section 30D — up to $7,500 for new EVs and $4,000 for used) was repealed by the One Big Beautiful Bill Act and ended on September 30, 2025. Any vehicle purchased on or after October 1, 2025 receives no federal purchase credit, so MotiveGrid applies no federal credit to any 2026 vehicle’s cost of ownership.
What We Don't Model
- What it really costs to own a car — the full picture in plain language
- The hidden costs of car ownership — depreciation, fees, and the line items buyers miss
- Depreciation: the cost that wrecks budgets — why the biggest cost is invisible
- Cheapest cars to own — the models that come out ahead
Last updated: May 2026 (v2 scoring + own TCO models) · hello@motivegrid.com
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