Quick answer
Three things move pump prices: taxes, supply, and competition. Taxes vary by state and city. Supply varies by how far you are from a refinery or pipeline terminal and whether you need a special fuel blend. Competition varies block by block — same brand, same city, two prices.
Taxes do most of the heavy lifting between states
Federal gas tax is 18.4¢/gal everywhere. State and local taxes add anywhere from ~9¢ (Alaska) to ~70¢ (California, including underground storage and carbon-program fees). That's most of the gap you see when you cross a state line.
Refinery and pipeline geography sets the regional baseline
Gulf Coast cities sit next to dense refining capacity, so wholesale prices there are usually the lowest in the country. The Rockies and the Northeast pay more because product has to travel further by pipeline, rail, or barge. When a refinery goes down for maintenance, regional prices spike before national headlines catch up.
Special fuel blends add cost where they're required
California requires CARB gasoline year-round. Many large metros require Reformulated Gasoline (RFG) in summer to meet ozone rules. Both cost more to produce, ship, and store. Cross out of a blend zone — even a few miles — and prices can drop noticeably.
Brand and station-level economics explain the rest
| Factor | Typical impact on pump price |
|---|
| Major brand (Shell, Chevron, BP) vs. unbranded | +5–20¢/gal |
| Highway / travel center markup | +10–30¢/gal vs. nearby |
| Costco / Sam's Club / supermarket fuel | −10–25¢/gal vs. nearby |
| Cash vs. credit posted price | +5–10¢/gal on credit |
What drivers can actually do
- Fill up across the state line when you're close to one with lower taxes.
- Use a price app on routes you drive often — the same station is rarely cheapest week to week.
- Avoid travel-plaza pricing unless you need food, restrooms, or DEF.
- Plan trips with the route fuel planner to see whether a known-cheap station is worth a detour.
- Pay attention to the break-even math: a 30¢/gal savings on a 12-gallon fill is $3.60 — not worth a 10-mile detour in most vehicles.
What you can't change
You can't out-drive taxes, refinery outages, or blend requirements. Sometimes the cheapest station in your zip code is still the most expensive one in the state — that's structure, not bad shopping.
A note on these numbers
Tax figures and station markups are estimates from public sources. Verify current taxes and posted prices for any decision with real money on the line.
Last reviewed by FuelHere Editorial on June 15, 2026.
