Ten cents a litre comes back on 8 September. Your own tank is the small part

Labour Day, Monday 7 September, is the last day of the federal fuel tax holiday. From Tuesday 8 September the excise tax is back at 10 cents a litre on gasoline and 4 cents on diesel, and nobody is going to send you a letter about it. The honest arithmetic first, so you do not overreact: a van doing 300 km a week pays roughly $187 a year more. The reason to keep reading is not your own tank. It is the fuel surcharge line on your supplier invoices, and the fact that gasoline is already 25.7% dearer than a year ago with this tax sitting at zero.

The date, the rates, and what actually moves

The federal excise tax on fuel was set to 0 cents a litre on 20 April 2026 and stays there until Labour Day, 7 September, inclusive. On Tuesday 8 September 2026 it returns in full:

• 10 cents a litre on gasoline and unleaded aviation gasoline
• 4 cents a litre on diesel fuel and aviation fuel
• 11 cents a litre on leaded aviation gasoline

This was legislated, not a discretionary pause someone can quietly leave in place. It went through as part of Bill C-30, the Spring Economic Update 2026 Implementation Act, which received Royal Assent on 18 June 2026. The rate applies by delivery and import date, so fuel delivered to a purchaser or imported before 8 September is still taxed at zero.

Provincial fuel taxes were never part of this. Only the federal line went to zero, and only the federal line comes back.

The tax-on-tax bit that is not really your cost

Here is the calculation every consumer article will run. GST/HST is charged on the excise tax as well as on the fuel itself, so at an Ontario pump on 13% HST the 10 cents lands as about 11.3 cents. Natural Resources Canada confirms the base: the GST/HST is charged on the federal excise tax and on provincial road taxes, not just on the fuel.

That figure is correct for a household. It is the wrong number for you.

If you are GST/HST registered and the fuel is used in your business, the GST/HST you pay on it comes back as an input tax credit, to the extent the fuel is used in your commercial activities. So the cost that actually reaches your profit is 10 cents a litre on gasoline and 4 cents on diesel, flat. Leave the sales tax out of your model.

It is a small distinction that stops you building a price decision on a number that is 13% too big.

Your own vehicle is a rounding error, and it is worth saying so

Work it through on a van, because a lot of you have one.

• 300 km a week is 15,600 km a year
• at 12 litres per 100 km, that is about 1,872 litres
• at 10 cents a litre, that is about $187 a year, or about $75 if it runs on diesel

For scale, the average household saving from the whole five-month holiday was estimated at $124 by the Parliamentary Budget Officer. This is not the event that decides your year.

So do not add a delivery surcharge over $187, and do not put a sign in the window about fuel costs. If your instinct was to reprice something this week because the gas tax came back, that instinct is aimed at the wrong number.

The place it actually reaches you is someone else's diesel

Nothing you sell walked in. The coffee, the colour, the gloves, the retail stock, the linen, all of it arrived on a truck, and that truck runs on the diesel line above. You do not pay that 4 cents directly. You pay it inside a delivery charge or a fuel surcharge, priced by someone whose costs you cannot see.

So spend twenty minutes on this, not on your own fuel card:

Pull your last three invoices from your two biggest suppliers and find the fuel surcharge. It is usually a separate line, often a percentage rather than a dollar amount. Then ask each supplier two questions in writing. What is the surcharge on 8 September, and what is it a percentage of?

The second question is the one they do not expect. A surcharge on the full invoice value behaves very differently from one on the delivery fee, and the difference compounds every week for the rest of the year.

And ask a third question of your own records first: did that surcharge ever come down between April and now? If your suppliers passed you nothing when the tax fell, you have learned something useful about how to read the increase they send you in September.

Fuel is up 25.7% with this tax already at zero

Statistics Canada published July's inflation numbers on 17 August 2026. All-items CPI was 3.0% year over year. Gasoline was up 25.7% in July, after 20.5% in June, pushed by the conflict in the Middle East, the blockade of the Strait of Hormuz and the partial closure of Red Sea shipping routes in late July.

Read those two facts together and the shape of September is clear. Ten cents is not a big number. It is a cushion being pulled out from under a price that has been climbing hard anyway, and the freight in your supply chain has been absorbing that climb all summer.

Someone will ask Ottawa to extend it. Price your plan as though they say no

The pressure is real and public. Ontario's premier wrote to the prime minister on 7 August 2026 asking for the suspension to run until at least 1 January 2027, or to be made permanent. As at today, Ottawa has not announced a decision either way.

Extending it is not free. The Parliamentary Budget Officer costed the current five-month holiday at $2.1 billion in 2026-27, on the assumption that the whole saving reaches consumers. The Department of Finance put the total relief at over $2.4 billion.

You cannot forecast this, so do not try. Write a trigger instead of a date: if the excise tax returns on 8 September, here is the specific thing I do. If Ottawa extends it next week, your trigger simply never fires and you have lost nothing. That is the whole advantage of deciding in advance.

What a buyer reads in a cost you did or did not pass on

This is where a small tax becomes a real signal about what your business is worth.

Anyone buying an owner-operated business normalises the last 12 to 24 months of earnings, and the line they study hardest is gross margin as a percentage, month by month. Not the dollars. The percentage. A margin that holds steady while input costs swing says the business has pricing power and an owner who acts. A margin that dips with every cost increase and never climbs back says the business absorbs whatever the market does to it, and a buyer prices that in.

April to September has handed you a free experiment on exactly that question. Input costs fell a little in April and rise again in September, and both moves are documented, dated and outside your control. So look at your own numbers before anyone else does. Did your gross margin percentage improve at all this summer? If it did not, either your suppliers kept the saving or you gave it to your customers without deciding to.

Either answer is fine. Not knowing is the expensive part, because profit that arrives by accident is exactly the profit a buyer refuses to pay a full multiple for.