Site methodology: where the numbers come from
I pull EIA every Monday afternoon ET when the weekly retail survey lands. AAA comes in every morning around 6 a.m. ET. GasBuddy comes in twice a day. Every price on this site carries an inline source stamp telling you which feed it came from and when it was last pulled. [EIA · 13 Jul 2026]
What I publish
Regular and on-highway diesel state averages for all 50 US states plus DC. National averages for both fuels. PADD groupings. The five cost-stack slices for each state. Per-state cost-to-fill-a-tank and cost-per-mile calculators.
What I do not publish
Station-level prices. Real-time intraday updates. Branded affiliate data feeds. I have no commercial relationship with any station, refiner, or fuel-card vendor.
The three upstream sources
- EIA. The US Energy Information Administration runs the Weekly Retail Gasoline and Diesel Prices survey. Monday morning collection, Monday afternoon release. State-level series for the 10 largest states; aggregate PADD series otherwise.
- AAA. The AAA Daily Fuel Gauge Report aggregates OPIS daily station feeds. State and metro level. Updated each morning around 5 a.m. ET.
- GasBuddy. Crowdsourced station prices from app users. Largest sample by station count, smallest by survey rigour.
Why I show all three
They disagree. When the three diverge by more than 5 cents per gallon, the EIA weekly is the slowest-moving anchor and GasBuddy is the fastest. The site's per-row source stamp tells you which one is speaking.
State excise data
From the American Petroleum Institute's gasoline tax map and the Tax Foundation 2026 ranking. [API · 13 Jul 2026] [Tax Foundation · 13 Jul 2026]
Federal excise
From FHWA Highway Statistics: 18.4 cents per gallon gasoline (including the 0.1 cent LUST), 24.4 cents per gallon diesel. Unchanged since 1 October 1993.
Refresh cadence
- Monday afternoon ET: EIA weekly retail and on-highway diesel.
- Every morning 6:14 a.m. ET: AAA daily fuel-club averages.
- Twice daily: GasBuddy spot pull.
- Once per quarter: state excise table refresh against API and Tax Foundation.
How to cite this site
CC BY 4.0. Attribute to gaspricesbystate.com with a link back. Machine-readable export at /data/.