Why Costco’s petrol is so cheap: the surprising economics behind the warehouse giant’s fuel strategy
Costco’s petrol prices reliably sit below those of virtually every competitor within driving distance — often by 20 cents or more per gallon. The reasons have nothing to do with inferior fuel. They have everything to do with a business model built around membership fees, deliberately thin fuel margins, and the calculated use of cheap petrol as a tool to lock in loyal customers and keep them returning to the warehouse.
Membership Fees Do the Heavy Lifting
Costco’s model runs on annual membership fees rather than product markups. Those fees — $65 for Gold Star or Business, $130 for Executive — generate around 70% of the company’s gross profit.
That cushion lets Costco price fuel at margins thinner than a conventional station can sustain. Where competitors depend on fuel profits, Costco largely does not.
Cheap Fuel as a Membership Driver
Petrol is among Costco’s most tangible member benefits. A driver who saves 20 cents per gallon on 300 gallons annually can recover the entire $65 Gold Star membership fee at the pump alone.
That arithmetic turns the fuel station into a retention tool. Members who receive consistent savings at the forecourt are less likely to let their subscriptions lapse.
How the Pricing Strategy Works in Practice
Costco petrol typically costs $0.05 to $0.40 per gallon less than nearby competitors. When wholesale costs spike, Costco absorbs more of the increase rather than passing it fully to members.
When prices ease, the discount narrows but persists — usually $0.05 to $0.15 below competitors. The consistent savings give members a tangible, recurring reason to renew each year.
What Members Actually Get at the Pump
Costco sells Kirkland Signature fuel at roughly 550 U.S. stations, in regular unleaded, premium and diesel grades. The fuel holds TOP TIER certification — a standard that mandates higher detergent levels than federal minimums.
Pumps are open only to members. That requirement links the fuel station to the warehouse next door, encouraging shoppers to browse the store on the same visit.
Fuel as a Signal During Rising Prices
Costco has sold petrol since the mid-1980s, expanding its forecourt network substantially through the 1990s. Fuel now accounts for approximately 10% of total net sales — a significant revenue stream by any measure.
During price surges, demand at Costco pumps rises sharply. In 2025, the company extended station operating hours during a period of elevated prices and reported record fuel sales.
