Gas Prices in Round Rock, TX Today

Round Rock drivers are paying around $3.33 per gallon for regular unleaded as of late March 2026, slightly below the Texas average of $3.42 and a significant discount from the national average of $3.91. Round Rock's position just north of Austin on I-35 gives it access to a high-volume competitive fuel corridor without the full premium of Austin's urban market.

The I-35 Advantage and the Austin Premium Avoidance

Austin's gas prices are consistently higher than the state average, driven by high commercial real estate costs, a tech-industry wage base that reduces consumer price sensitivity, and a city council that has periodically added local fees and requirements that increase operating costs. Round Rock is close enough to share Austin's distribution infrastructure but far enough that it operates under Williamson County economics, not Travis County ones.

Williamson County has lower commercial property taxes and real estate costs than Travis County, which feeds directly into station operating costs. A station operator in Round Rock can afford to charge less per gallon than an equivalent station in North Austin because their overhead is lower.

Dell Technologies' campus on N. IH-35 is Round Rock's largest employer, with tens of thousands of employees commuting daily. That concentration of working professionals with predictable commute patterns creates anchor demand for the stations along the Dell corridor, and enough competition among those stations to keep margins competitive.

Where to Find the Cheapest Gas in Round Rock

Round Rock has only three ZIP codes, so the variation is meaningful:

• 78664, East Round Rock along US-79 and the eastern I-35 frontage, highest station density and best price competition in the city; this is where to fill up
• 78681, West Round Rock near Avery Ranch and SH-45, newer master-planned development with higher rents built into station costs, prices run 5–10 cents above 78664 on most days
• 78665, North Round Rock near Hwy 29 and I-35, good mix of highway corridor stations with competitive pricing; second-best ZIP for prices after 78664

The Sam's Club on I-35 in 78664 is the most reliable cheap-fill anchor in Round Rock and consistently prices 15–20 cents below the city average. Costco has a location in nearby Cedar Park that draws many Round Rock residents for the same reason.

The Premium Outlet Mall Effect

Round Rock Premium Outlets on I-35 draws significant regional traffic from Austin, Georgetown, Pflugerville, and points farther out. On weekends, the stations along the I-35 frontage near the outlets see out-of-area visitors who don't know local price patterns and are more likely to accept higher prices for convenience. The stations nearest the outlet mall exits, particularly on exit 256, take advantage of this. They're not the cheapest in town; they're the most convenient for someone who doesn't know Round Rock.

Local residents are better served by stations a mile or two off the main I-35 frontage in 78664 or on the RM-620 corridor in 78681.

Versus Cedar Park and Pflugerville

Round Rock's neighbors price similarly, with Cedar Park occasionally a few cents cheaper due to lower commercial density near the SH-183A toll corridor. Pflugerville, to the southeast, runs 2–4 cents below Round Rock on average because of its positioning closer to Austin's wholesale distribution terminals without the outlet-mall-corridor premium.

If you're commuting from Round Rock to Austin and prefer not to fill up at the Dell corridor stations, checking Pflugerville prices on your commute route can occasionally offer a better deal.

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