Methodology & data sources

Every number on Gasolytics comes from a named public source — nothing is estimated by a model or filled in by hand. This page says exactly where each figure comes from, how often it updates, and — just as important — what the data can’t tell you.

Gas prices: AAA daily averages

State and metro averages for all four grades (regular, midgrade, premium, diesel) come from AAA’s daily gas price survey, read once a day. AAA partners with OPIS, which aggregates price reports — mostly card-transaction data — from roughly 130,000 US stations. State averages change once per day at the source, which is why the site says “updated daily” rather than live ticks.

Posted prices, not what people actually pay

The averages describe posted prices, not transactions. A volume-weighted average — what drivers actually pay — would run meaningfully lower, because expensive stations post high prices but pump fewer gallons while the discount warehouse-club line stretches around the block. That transaction-weighted data exists (card processors and OPIS have it) but it is not public, so every free tracker, including this one, shows posted-price averages. Expect a savvy fill-up at a discount chain to run well under your state’s average — in California often 60–90¢ under.

Coverage limits

The survey covers stations that report through the price feed. Remote areas with cash-heavy or non-reporting stations effectively never enter the average — rural Alaska is the clearest case, where real posted prices of $7–10/gal along remote roads are invisible to the statewide number, which tracks the road system and population centers. There is no manual outlier exclusion anywhere on this site: gaps are a matter of coverage, not trimming.

Blends, octane rules, and tax holidays are baked in

The map shows what the “regular” button costs at the pump. It does not normalize for fuel-blend differences (E15 vs E10, summer vs winter blends), state octane floors, or temporary tax policy. When a state suspends its gas taxes — as Indiana did through August 6, 2026, worth roughly 60¢/gal at July rates (a 36¢ excise tax plus the suspended sales tax on gasoline) — its average genuinely drops for exactly that period. Cross-border comparisons should keep that in mind — the gas-tax page tracks each state’s rates and flags active suspensions.

Price history

AAA publishes no history, so Gasolytics builds its own: one snapshot per day, stored since early June 2026 (45 daily snapshots so far). Every sparkline, trend, streak, and week/month change on the site is computed from that snapshot series — which also means trends can only reach back as far as the archive does.

EV numbers: EIA residential rates, home charging only

Electricity prices come from the EIA’s monthly average residential rate per state (published on ~2-month lag). Cost per mile assumes 3.5 mi/kWh for EVs and 26 MPG for the gas comparison — both constants are shown on every page that uses them. Two honest caveats: the statewide average hides a wide utility spread (some investor-owned territories run far above it, some municipal utilities far below, and EV time-of-use plans lower it further), and everything is home charging — public fast charging has no clean public price data, so we say so instead of estimating it. See EV vs gas.

Affordability & per-capita figures

The affordability ranking prices a fixed benchmark year of driving — 12,000 miles at 26MPG — at each state’s current AAA regular average, divided by median household income (Census Bureau CPS ASEC 2024). Charging-station counts come from the Department of Energy’s AFDC station database, refreshed daily; per-capita ranks use 2025 Census estimates.

What this site is

A free side project — no ads, no accounts, no tracking beyond anonymous page analytics, and the underlying data is never sold. Found a number that looks wrong? It almost always traces to one of the limitations above, but the fastest way to get it fixed is the contact link on .

See also: price trends · affordability · trip calculator