Methodology
How we calculate what you see
Every number on this site is either published by the U.S. Energy Information Administration or computed from it by a formula written out below. This page exists so you can check our work.
Where the prices come from
Retail fuel prices come from the EIA’s weekly retail gasoline and diesel price survey. The EIA collects prices from roughly 1,000 retail outlets across the country each Monday and publishes the results around 10am ET the following morning. We pull them from the EIA Open Data API and cache each series for an hour.
Crude oil prices are the EIA’s spot price series for West Texas Intermediate at Cushing, Oklahoma, and for Brent. These are spot benchmarks, not futures settlements, and they are not real-time — the EIA publishes them with a short lag.
The most important caveat on this site: these are weekly regional averages, not the price at your local station. A station three miles from you can easily be 40¢ away from the regional average in either direction. Use this site to understand the trend and the reasons behind it; use a station-level app to decide where to actually fill up.
What we compute, and how
The analysis on each region page is derived from the trailing 52 weeks of that region’s regular-grade series. The formulas are in lib/regionAnalysis.js in our codebase, and they are these:
| Figure | How it is calculated |
|---|---|
| Position in range | The share of the last 52 weekly observations that were at or below the current price. 0% means this is the cheapest week of the year; 100% means it is the most expensive. |
| Volatility | Coefficient of variation — the standard deviation of the last 52 weeks divided by their mean, as a percentage. We use this rather than raw standard deviation so that an expensive market and a cheap one can be compared directly. |
| Gap vs national | Current regional price minus the current national average. We also show the region’s average gap over the same 52 weeks, because a region can be expensive in absolute terms while being unusually cheap by its own standards. |
| Crude share of pump price | WTI spot price divided by 42 gallons per barrel, expressed as a share of the retail price. This is an approximation: it ignores refinery yield, meaning a barrel does not become 42 gallons of gasoline, and it ignores the two-to-six-week lag between crude moves and pump prices. |
| Tax share | EIA’s total state burden (excise plus other per-gallon taxes and fees) plus the 18.4¢ federal tax, as a share of the retail price. We use the total rather than excise alone because excise badly understates states that levy sales tax on fuel. Shown for individual states only — multi-state regions have no single rate. |
| Annual fuel cost | Current price × 480 gallons, which is roughly 12,000 miles a year at 25 mpg. A 15-gallon tank is assumed for the fill-up figure. Both are illustrative benchmarks, not a claim about your vehicle. |
Where the tax figures come from
Tax figures come straight from the EIA’s federal and state motor fuels tax table, updated July 2026. You can download the same spreadsheet we use and check every figure against it.
We report three numbers per state, because they are not interchangeable: the excise rate, other per-gallon taxes and fees (inspection, environmental and storage-tank charges, plus the per-gallon equivalent of fuel sales tax where a state levies one), and the total of the two. We rank and headline on the total. Quoting excise alone is a common way to mislead: New York has the lowest headline excise in the country at 8¢ and a real state burden three times that.
Two things still sit outside these figures. Local-option taxes set by counties and cities are not included. Neither are carbon programme costs — California’s cap-and-trade and Low Carbon Fuel Standard, and Washington’s cap-and-invest — because they are embedded in the wholesale price rather than charged per gallon at the pump. In both states the real burden is therefore higher than we show, and we say so on those region pages rather than folding an estimate into the number.
Where the written analysis comes from
The structural background on each region — refining capacity, supply routes, blend requirements — is researched against the sources listed below, checked before publication, and carries a “last reviewed” date on every region page so you can see how fresh it is. Where a claim cannot be tied back to one of those sources, we take it out rather than leave it standing.
This section used to be produced from a single template applied to every region, which gave each page the same six paragraphs with the region name swapped in. We replaced it because it told a reader nothing the price alone did not already say. Each region now gets facts specific to that market — the refineries that actually serve it, the blend it actually burns, the taxes it actually levies — or, if we have nothing specific and checkable to say, no section at all.
What this site does not do
- It does not show station-level prices. The EIA survey is regional. We have no data on individual forecourts.
- It does not forecast prices. We describe what has happened and identify what tends to move a given market. We do not predict where prices go next, and nothing here is financial advice.
- It is not real-time. Retail prices update weekly. The dashboard's refresh indicator means we re-checked the API, not that the underlying price changed.
- It does not cover every state. The EIA publishes weekly retail data for a subset of states. We only show regions where a real series exists rather than interpolating one.
Corrections
If a figure here is wrong, we want to know. Email hello@getpumprate.com with the page and the number in question and we will check it against the source. Substantive corrections are noted on the page they affect, and the “last reviewed” date is updated when we revise the written analysis.