Costco Gas in Canada vs the US: Why Prices Differ So Much

Costco gas in Canada is priced in cents per litre and Canadian dollars, and US Costco gas in dollars per gallon, so the two are hard to compare at a glance. We converted our own daily prices to the same units to answer a simple question: is the Costco Canada gas price really higher than in the US, and if so, why? The answer changes depending on which border you stand at.

Short answer: On our September 29, 2026 reading, the average Costco Canada gas price was 173.0¢/L, and the US Costco average ($4.643/gal) converted to 174.0¢/L at the Bank of Canada rate. So nationally they were level. Border pairs tell a different story: Quebec and New Brunswick Costcos were 27 to 34¢/L dearer than Vermont and Maine, while BC was cheaper than Washington. Most of the gap comes from taxes, which differ far more between provinces and states than the fuel itself does.

Costco Canada gas price vs the US: the national comparison

To compare like with like, we converted US prices with the formula our Bellingham cross-border post uses: USD per gallon × USDCAD rate ÷ 3.78541 × 100 = ¢/L in Canadian dollars. The Bank of Canada's rate for September 29, 2026 was 1.4188.

Puerto Rico is excluded because its prices are posted per litre. The US average is pulled up hard by California, where 128 Costcos averaged $6.05/gal. Leave California out and the US Costco average drops to 159.5¢/L, about 13.5¢ below Canada's. For most Canadians, the useful comparison is the state next door, not the national average.

Costco gas prices at the border: state vs province

Here are average Costco regular prices in neighbouring states and provinces on September 29, 2026, all in Canadian cents per litre. Some averages rest on very few stations, which we note.

Costco Windsor posted 171.9¢/L, while Costco Madison Heights in suburban Detroit was $4.459/gal, or 167.1¢/L: less than 5¢ apart. Costco Colchester, Vermont was $4.199/gal (157.4¢/L), while Costco Sherbrooke was 186.9¢/L, nearly 30¢ higher.

These are pump prices converted at the Bank of Canada rate. A Canadian card usually adds about 2.5% on US purchases, and the drive and border wait cost extra; our Bellingham vs Langley and Abbotsford analysis works through whether a trip pays.

How prices moved in both countries over the last 30 days

US Costco prices rose faster than Canadian ones in September, and the weaker loonie amplified it.

On August 31, Canadian Costco gas was about 10.6¢/L dearer than the US average. By September 29 it was 1¢ cheaper. Roughly four-fifths of that swing came from US prices rising in US dollars, and the rest from the exchange rate.

Within Canada the month was uneven. Saskatchewan's three Costcos jumped from 136.9 to 174.6¢/L, Manitoba rose 22.3¢ and Alberta 15.5¢, while Ontario slipped 1.1¢. The Prairies buy from a supply system tied to the US Midwest, so Midwest refinery problems can move prices there quickly, as a Kalibrate analyst has pointed out. We don't know the specific cause of this month's jump, so check the Canada price page for the current picture.

Why Costco gas prices differ between Canada and the US

Costco prices both countries the same way: it buys at local wholesale prices and sells on a thin margin (see why Costco gas is so cheap). So the gap comes from what surrounds Costco: taxes, the exchange rate and regional supply.

Taxes: the biggest single factor

Canada's normal federal fuel taxes are a 10¢/L excise tax plus 5% GST (or HST, which folds in the provincial sales tax). Two things are unusual in 2026:

• The federal excise tax is suspended. Ottawa stopped collecting it on April 20, 2026. On September 2 it announced the pause will run to January 31, 2027, with a half rate (5¢/L) from February 1 and the full 10¢/L from April 1, 2027. The legislation, Bill C-38, was tabled on September 22. So the 173.0¢/L average contains no federal excise tax. Expect about 10.5 to 11.5¢/L more, with sales tax, when it returns.
• The consumer carbon tax is gone. The federal fuel charge (17.6¢/L on gasoline by the end) was set to zero on April 1, 2025, and BC ended its own carbon tax the same day. Quebec is the exception: its cap-and-trade system still adds a cost at the wholesale level, usually estimated at 8 to 10¢/L.

Canada also taxes the tax. GST and HST are charged on the full pump price, and the Canada Revenue Agency's guidance confirms that federal excise and provincial fuel levies are part of the amount the sales tax applies to. In Ontario, 13% HST on a 167¢ litre is about 19¢/L, more than twice the province's 9¢ gas tax.

The US charges a federal 18.4¢ per gallon (4.9¢ US per litre), and states add their own taxes. Most states don't add general sales tax on gasoline, although a few, like New York and California, do.

Tax per litre: provinces vs border states

Statutory rates as of September 2026. US rates are the EIA's July 2026 totals converted to ¢/L CAD at 1.4188.

What's in a litre of Costco gas: a tax breakdown

Here is how the September 29 Costco prices split into tax and everything else (fuel, refining, freight and Costco's margin). Sales tax is backed out of the pump price; all figures are ¢/L in Canadian dollars.

*Quebec's cap-and-trade cost sits inside the pre-tax price.

Before tax, Alberta, Ontario, Quebec and Michigan all land within about 4¢/L of each other. That matches what Kalibrate reports: once you account for the exchange rate, Canadian and US wholesale prices generally run at par. The West Coast is dearer on both sides of the border before a cent of tax, which is a supply story (below).

The exchange rate

US wholesale gasoline is priced in US dollars, and Canadian wholesale prices follow the same benchmarks. When the loonie weakens, Canadian pump prices rise even if nothing else changes. At September 29 prices, each 1¢ move in the USD/CAD rate shifts a $4.64 US gallon by about 1.2¢/L. Kalibrate notes that "a weak Canadian dollar leads to higher pump prices."

Crude oil matters less than refined gasoline markets

Western Canadian crude often sells at a discount to West Texas Intermediate, which leads to a common question: why doesn't that make Canadian gas cheap? Because pump prices follow refined gasoline, not crude. The Competition Bureau has said Canadian wholesale gasoline tracks the New York Harbor spot price, and Ontario's government names New York Harbor as the benchmark for Toronto. The Canadian Fuels Association says Canada is "part of an integrated North American market" and there is "no such thing as a purely 'made-in-Canada' fuel price."

Refining and regional supply

Where the nearest refineries are, and how full they run, sets the pre-tax price. Kalibrate says BC's refining capacity is below its consumption, so it relies on imports and competes with the US West Coast for supply, which is why both Langley and Bellingham carried a high pre-tax price. Costco itself doesn't refine; it buys from whoever supplies the region, as we explain in where Costco gets its gas.

Seasonal blends

Both countries switch to cheaper winter-grade gasoline in the fall (the US summer season for retailers ends September 15). Blend timing can nudge prices for a few weeks, but it doesn't explain gaps of 20¢/L or more.

Why Costco Canada gas prices vary so much by province

On September 29, our provincial averages ran from 160.7¢/L in Alberta to 216.9¢/L in Newfoundland and Labrador, a 56¢ spread. The main reasons:

• Sales tax. The GST-only provinces (Alberta, BC, Saskatchewan, Manitoba) charge 5%. HST provinces charge 13 to 15%, which at these prices adds roughly 12 to 17¢/L more than GST alone.
• Metro Vancouver's TransLink tax. The Lower Mainland pays 27¢/L of provincial motor fuel tax against 14.5¢ in most of BC. That's why Abbotsford (176.9¢/L) was 15¢ below Langley (191.9¢/L).
• Quebec. The highest fuel tax (19.2¢, 22.2¢ around Montreal), the highest combined sales tax (14.975%) and the only remaining carbon price. Quebec's Régie de l'énergie also sets a weekly minimum price, which puts a floor under discounting.
• Atlantic price regulation. All four Atlantic provinces regulate pump prices, according to the Canada Energy Regulator: New Brunswick and Newfoundland and Labrador set a maximum, while Nova Scotia and PEI set a minimum and a maximum. Regulated prices are built from New York Harbor benchmarks plus set margins, freight and taxes.
• Alberta's low tax, and it's about to get lower. Alberta pays 13¢/L and 5% GST. From October 1, 2026, the province suspends its fuel tax through at least December 31 because WTI averaged over US$90 a barrel, so Alberta Costco prices should drop by about 13.7¢/L with GST.

Newfoundland stands out even before tax. Its only Costco, in St. John's, showed about 181¢/L before tax, against about 140¢ in Ontario and Alberta, even though NL has the lowest provincial fuel tax (7.5¢). The island no longer has a gasoline refinery (Come By Chance now makes only renewable diesel), so fuel comes in by tanker, and the regulated maximum includes freight and set margins. We have one station there, so treat the figure as a snapshot.

Is Costco gas American or Canadian?

Costco is an American company, based in Issaquah, Washington, but the gas at Canadian gas bars comes from the Canadian wholesale market. Costco Canada says it buys typically unbranded gasoline "from the same major refineries and distributors that supply all of the gas stations in an area," not from a single supplier. Depending on the region, that fuel may be refined in Canada or imported, just as it is for other stations nearby. Our post on where Costco gets its gas has the details, and the newcomer's guide to Costco gas bars explains ¢/L pricing.

Frequently asked questions

Is Costco gas cheaper in Canada or the US?

It depends on where you compare. On September 29, 2026, the average Costco regular price was 173.0¢/L in Canada and 174.0¢/L in the US after conversion, but excluding California the US average was 159.5¢/L. Near most borders, US Costcos were cheaper, except Washington, which was dearer than BC.

How do I convert a US Costco gas price to cents per litre?

Multiply the US price per gallon by the US-to-Canadian exchange rate, divide by 3.78541, and multiply by 100. At the September 29, 2026 rate of 1.4188, $4.643 per gallon works out to 174.0¢/L.

Does the price at Canadian Costco gas bars include the federal excise tax right now?

No. The federal excise tax of 10¢/L on gasoline has been suspended since April 20, 2026, and Finance Canada plans to keep it at zero until January 31, 2027. A half rate is scheduled from February 1, 2027 and the full rate from April 1, 2027.

Is there still a carbon tax on Costco gas in Canada?

Not outside Quebec. The federal consumer fuel charge and BC's carbon tax both ended on April 1, 2025. Quebec's cap-and-trade system still adds an estimated 8 to 10¢/L at the wholesale level.

Why is Costco gas in Alberta cheaper than in the rest of Canada?

Alberta has 5% GST instead of HST, a moderate 13¢/L provincial fuel tax, and nearby refineries. From October 1, 2026, the province is suspending its fuel tax through at least year end, which should widen the gap further.

Why is Costco gas so expensive in Newfoundland?

St. John's had the highest Costco price in our data, 216.9¢/L on September 29, 2026. Newfoundland charges 15% HST and relies on fuel shipped in by tanker, and its prices are capped by a regulated maximum that includes freight and set margins.

Sources

• Bank of Canada Valet API, FXUSDCAD series — daily rates, 1.3866 on August 31 and 1.4188 on September 29, 2026.
• The Government of Canada extends the federal fuel excise tax relief, Finance Canada (September 2, 2026) — excise suspended since April 20, 2026, extended to January 31, 2027, 5¢/L from February 1, 2027.
• Minister Champagne introduces legislation to extend the federal fuel excise tax relief, Finance Canada (September 22, 2026) — Bill C-38, full rate returning April 1, 2027.
• The consumer carbon tax is gone as of today, CBC News (seen in search results) — fuel charge of 17.6¢/L ended April 1, 2025; Quebec's cap-and-trade remains.
• Application of GST/HST to Other Taxes, Duties, and Fees, Canada Revenue Agency — federal levies and non-prescribed provincial fuel levies are included in the amount GST/HST applies to.
• Motor fuel tax and carbon tax rates, Province of British Columbia — 27¢/L Vancouver area (18.5¢ TransLink), 20¢ Victoria, 14.5¢ rest of BC; carbon tax eliminated April 1, 2025.
• Fuel tax: fuel sellers, Alberta.ca — provincial fuel tax suspended from October 1, 2026 until at least December 31, 2026; Alberta suspending fuel taxes amid high oil prices, BNN Bloomberg (seen in search results) — WTI averaged US$90.54 in the review period.
• Ontario Budget 2025, chapter 1B (seen in search results) — gas tax kept at 9¢/L permanently.
• Manitoba government introduces permanent cut to provincial fuel tax (seen in search results) — 12.5¢/L from January 1, 2025.
• Fuel Tax, Saskatchewan eTax Services (seen in search results) — 15¢/L on gasoline.
• A Plan for Lower Taxes, Newfoundland and Labrador Budget 2026 (seen in search results) — gasoline tax permanently 7.5¢/L from April 1, 2026.
• Gas Tax by Province 2026, CheapGasCanada.com — cross-check for New Brunswick (10.87¢), Nova Scotia (15.5¢, HST 14%), Quebec (19.2¢, 22.2¢ Montreal) and the 8 to 10¢/L cap-and-trade estimate (an aggregator, verified July 2026).
• Federal and state motor fuel taxes, July 2026, US Energy Information Administration — federal 18.4¢/gal and state totals for WA, MI, MT, ND, VT, ME, NY; Michigan's prepaid sales tax ended January 1, 2026.
• Market Snapshot: Understanding the regulation of gasoline prices in Atlantic Canada, Canada Energy Regulator — which Atlantic provinces set maximum or minimum prices.
• Price Regulation, Consumers Council of Canada (seen in search results) — Quebec's weekly minimum price.
• Canadian gas prices explained, Kalibrate (September 2025) — Canada-US wholesale parity after exchange, weak loonie effect, West Coast supply.
• Gasoline Prices, Canadian Fuels Association — integrated North American market, no "made-in-Canada" price.
• Why Gasoline Prices Vary Across Canada, Natural Resources Canada — taxes as the most important factor in regional differences.
• Alberta drivers get relief at the pump, Yahoo News Canada and Competition Bureau concludes gasoline pricing examinations (both seen in search results) — Prairie prices tied to the US Midwest; wholesale tracks New York Harbor.
• Gasoline Reid Vapor Pressure, US EPA (seen in search results) — US summer season June 1 to September 15 for retailers.
• The Come By Chance refinery is producing fuel again, CBC News (seen in search results) — refinery converted to renewable diesel.
• Prices: costcogaspricedb.com daily readings, August 31 to September 29, 2026 (592 US stations excluding Puerto Rico, 78 Canadian stations).