For instance the US and Canada are both big fuel producers, but gasoline prices in Canada are much higher in Canada…
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Remember, though that, unless things have changed, an Imperial gallon contains 5 US quarts so the price per gallon could appear 25% higher because of that. And if it is sold in liters now, a liter is somewhat larger than a US quart.
There are no Imperial gallons involved here, and that is not why the price seems higher in Canada. There is a US gallon (3.8 litres; we never use gallons any more, neither US gallons nor Imperial gallons), and there is a US:Canadian exchange rate (with the USD being worth about CA$1.25, or inversely, one C$1 is worth almost exactly US$0.80. So to convert the Canadian price to the US price, you have to do 2 calculations: take the Canadian price per litre and convert it to the price per US gallon, by multiplying by 3.8, and then convert to US dollars by multiplying by the CAD:USD exchange ratio.
So the average price in Canada today, according to the CAA, is C$1.72/litre, meaning about C$6.54/US gallon, which is US$5.23/gallon. The AAA says that today’s average price in the US is US$4.22, so there’s a difference of about US$1.01. US taxes are higher in Canada, by about US$0.70/US gallon, so a little over two thirds of the price difference is just the different tax level.
Funnily enough, despite higher gas prices in Europe and Japan, their gasoline prices excluding taxes are even lower than they are in Canada and the USA, don’t ask me why: https://www.canadianfuels.ca/our-industry/gasoline-prices/. Their higher pump prices in most countries are because taxes are much higher there. Why Canadians, and especially Americans, are so resistant to higher taxes requires a sociological or political explanation that is beyond my ken, but my guess is that our societies are built around individual car ownership (and not walking, using bicycles, subways, tramcars and trains), so there is less popular support for increasing the cost of automobile use.
dtb