Ontario diesel prices

Ontario has the widest internal diesel spread of any Canadian province. In the Natural Resources Canada survey print dated 11 August 2026, Kitchener came in at 205.2¢/L and Sault Ste Marie at 228.2¢/L. That is a 23-cent gap inside one province, wider than the gap between most pairs of provinces.

Tax does not explain it. Ontario charges a single provincial fuel tax rate of 9 cents per litre on clear diesel everywhere in the province, a rate the government made permanent on 1 July 2025 after three years of temporary cuts from the previous 14.3 cents. Harmonized sales tax applies at the same 13 per cent in Sault Ste Marie as in Kitchener. The federal excise on diesel, normally 4 cents per litre, is suspended nationwide from 20 April to 7 September 2026. Every one of those figures is identical at both ends of the province.

What differs is the cost of getting the fuel there. Southern Ontario sits inside a dense supply network anchored on the refining and terminal capacity around Sarnia, with enough competing retail sites that no single operator sets the local price. Northern markets are at the end of a long haul, served by fewer suppliers, selling less volume. Diesel does not stop being a freight cost simply because it is the freight. Every kilometre between a terminal and a pump has to be paid for by someone, and in the north there are fewer litres to spread that cost across.

This is why a provincial average is a blunt instrument. Ontario's figure of 211.5¢/L in the same print is the unweighted mean of nineteen survey cities, and no single operator experiences it. A carrier running Windsor to Toronto sees the bottom of the range. One running Timmins to Thunder Bay sees the top. Both are described by the same number, and the number is useful for tracking direction over time rather than for predicting what a fill will cost.

One caveat on every figure here. The NRCan survey measures posted retail, not cardlock. If you run a fuel card, your actual cost is usually lower than the posted average, so use your card price rather than this number for planning a specific fill.