How we get the number.

Each week, after EIA's Monday release, we pull EIA Weekly Retail Gasoline Prices — the same series the U.S. Department of Energy publishes — and pair them with EPA fuel-economy records (the fueleconomy.gov dataset). Both sources are public, and we cite them inline on every page.

Where prices come from

EIA publishes weekly:

  • National average
  • 7 PADD regional averages (New England, Central Atlantic, Lower Atlantic, Midwest, Gulf Coast, Rocky Mountain, West Coast)
  • 9 state averages: CA, CO, FL, MA, MN, NY, OH, TX, WA

States not in EIA's per-state series fall back to their PADD regional average. Crowdsourced reports will overlay state averages once enough come in.

Current snapshot: $4.46/gal national, week of 2026-09-28.

How the calc works

Full-tank cost = tank size (gal) × $/gallon; typical fill = 85% of that. Miles per tank = tank × MPG. Annual cost = (miles/year ÷ MPG) × $/gallon.

Vehicle data: EPA Fuel Economy database (fueleconomy.gov), 30,600 variants spanning model years 1984–2027. Combined MPG = EPA-published city/highway average. Each variant — drivetrain, engine size, hybrid configuration — is preserved as a separate selectable option.

Tank capacity uses a 4-tier resolver: (1) year-range manufacturer spec for models with generational tank changes (Toyota Prius 3rd-gen 11.9 gal vs 4th-gen 11.3 gal vs 5th-gen 10.6 gal; Camry XV40 18.5 → XV80 13.2; F-150 12th-gen 26 → 13th-gen 23; Honda Civic/Accord by generation), with fuel-type splits for hybrid and plug-in variants sharing one EPA model name (2012-2015 Prius Plug-in Hybrid 10.6 gal vs regular hybrid 11.9 gal; Accord Hybrid 12.8 gal vs 14.8; Hyundai Santa Fe/Tucson PHEV, Kia Sportage PHEV) and trim or drive splits where the tank differs inside one model year (F-150 Raptor 36 gal; Camry all-wheel drive 14.4 gal vs 15.8); (2) flat manufacturer spec for 514 popular models (Mercedes E350, BMW 530i, Bentley Continental, Rolls-Royce Phantom etc.) — these figures carry no year and were checked against the current generation only, so they count as a spec for model years 2022 and newer and are shown as the current model's figure, not a spec, on older years; (3) both tables again on a shorter form of the model name, longest match first, for names EPA pads with extra words ("RX 450h" → RX; "Grand Highlander Limited/Platinum" → Grand Highlander) — that is a related model's figure, usually the right family but sometimes a different car, so it is shown as an estimate and never as a spec; (4) EPA vehicle class fallback for the long tail. Where a tank depends on something an EPA row does not record — the cab of an F-150, the grade of a Tundra — we show the smallest tank that model was sold with, say that it varies and give the range, and the calculator's tank field takes yours.

Where each tank figure came from, counted over all 30,600 variants at build time: 2,137 resolve by year-range spec and 3,023 by flat model spec — 5,160 rows on a manufacturer figure for that exact model. The rest are not: 191 are trucks whose tank varies by cab, grade or option and show the smallest one with its range, 7,305 show the current model's figure on a model year before 2022, 3,342 take a related model's figure, and 14,602 (48%) fall back to the EPA vehicle-class estimate, mostly pre-2010 model years. The calculator and every fill-up page label which tier the figure came from: "manufacturer spec", "varies by configuration: 26–36 gal — enter yours", "figure for the current model — older years may differ, check your manual", "estimated from a related model — check your manual", or "estimated from vehicle class — check your manual". The tank field in the calculator takes your own number, and an edit that disagrees with ours is logged (vehicle and gallons only, nothing personal) so wrong rows get found and fixed.

Fill-up cost is shown as a range. The low end is a typical fill — about 85% of nominal tank capacity × price-per-gallon — because nobody refuels from empty: most people pull in around the low-fuel warning, and the pump clicks off a touch short of the rated capacity. The high end is the full tank ceiling: nominal capacity × price-per-gallon.

What we don't do

  • No GasBuddy / AAA scraping. Their data is theirs. We're independent — by design.
  • No station-level real-time pricing. Weekly granularity is sufficient for budget decisions; station-level requires a paid feed or scraping (legal exposure).
  • No price predictions. We report what's happening, not what might.

Attribution

  • Map: a static SVG choropleth drawn with D3 from the us-atlas TopoJSON (public domain). No map tiles are loaded.
  • City data: the 51 most populous U.S. cities, hand-curated from U.S. Census Bureau population figures.