Cheapest Gas in Boulder, CO

Updated May 20, 2026 — Prices updated regularly from EIA data

$3.04

Lowest price at Costco in Boulder

Finding Cheap Gas in Boulder

Hunting down the lowest gas price in Boulder, Colorado is worth the effort. At $$3.04 per gallon at the cheapest outlet versus $$3.29 at the most expensive, you save $$3.75 on every 15-gallon fill-up.

Maximum Savings in Boulder

Choose Costco over Chevron

$0.25 per gallon

$3.75 per 15-gallon fill • $12.00 per year (est.)

Cheapest Brands in Boulder

Rank	Brand	Est. Price	Savings vs. Most Expensive
#1	Costco	$3.04	$0.25
#2	Speedway	$3.16	$0.13
#3	Circle K	$3.17	$0.12
#4	Sunoco	$3.20	$0.09
#5	Marathon	$3.21	$0.08
#6	BP	$3.23	$0.06
#7	Mobil	$3.24	$0.05
#8	Exxon	$3.25	$0.04
#9	Shell	$3.27	$0.02
#10	Chevron	$3.29	$0.00

Gas Saving Tips for Boulder Drivers

Keep your tires properly inflated to the manufacturer's recommended PSI — under-inflated tires reduce fuel economy by up to 3%, costing you money every mile.
Accelerate and brake gradually. Aggressive driving can reduce fuel economy by 15-40%, directly increasing how often you fill up.
Track weekly price cycles in your city — most markets follow predictable weekly patterns. Identifying yours and filling on low-price days saves 5-15 cents per gallon consistently.
Fill up before holiday weekends. Memorial Day, Fourth of July, and Labor Day consistently see 10-25 cent price spikes as demand surges. Topping off Thursday before a holiday weekend beats the rush.
Download the Upside app for cashback on gas purchases — users report average savings of 20-30 cents per gallon on qualifying transactions.