Data Sources & Methodology

Data updated: February 16, 2026

What This Page Covers

This page explains where our core inputs come from, how we normalize those inputs, and how calculator outputs are computed for state, city, and vehicle pages.

Primary Data Sources

EIA (U.S. Energy Information Administration): residential electricity benchmarks used for state-level rate baselines. Sources: EIA Open Data portal and EIA electricity price FAQ.
NREL AFDC (U.S. DOE): charging-station availability and network coverage context used in state and city infrastructure summaries. Source: NREL AFDC API docs.
AAA: national gasoline price benchmarks used in EV vs gas comparisons. Source: gasprices.aaa.com.
IRS: federal tax and credit eligibility context for EV-related tax guidance language. Sources: IRS Form 8911 (charger credit) and IRS clean vehicle tax credits guidance.

Calculation Framework (High-Level)

Vehicle energy need is estimated from efficiency (miles/kWh).
Monthly energy need is split by your charging mix (home/public percentages).
Home and public charging costs are calculated separately, then combined.
Gas comparison uses standardized MPG and fuel-price assumptions for parity.
Annualized outputs scale monthly results for budget-level planning context.

Normalization Rules

Rates are represented in USD per kWh.
Costs are rounded for readability while preserving comparison utility.
Station counts are used as coverage indicators and may vary from live maps by update timing and availability filters.
Geographic summaries use consistent state/city slug mappings to prevent routing mismatches.

Update Frequency and QA

Core datasets are refreshed on a recurring schedule. Each refresh includes validation checks for missing fields, out-of-range values, and broken route references before publication.

Important Limitations

Figures on this site are planning estimates. Your bill can differ based on tariff structure, time-of-use periods, weather, driving behavior, battery condition, and local fees.

For financial or tax filing decisions, consult official utility tariffs and an advisor. See also Site Terms and Privacy Policy.

Feedback and Corrections

If you see a mismatch or stale value, contact us with the page URL and exact field. Use the Contact page to submit a correction request.