Diesel Up 23.9 Cents in September: What Can a Fuel Card Actually Save?

When diesel jumps, the first question about a fuel card is usually simple: how much cheaper will my fuel be?

The answer needs more than a discount number. Where you fill, how the supplier sets your price and what fees you pay all affect the saving. When thousands of dollars are leaving your account every week, payment terms matter too.

Kalibrate’s September 2026 snapshot puts Canada’s national retail diesel average at 260.7 cents a litre at month-end—up 23.9 cents from the end of August and 107.6 cents from a year earlier. Those are national retail benchmarks. Your local pump price and contracted fuel-card price may be different.

What that increase means for one truck

Take a truck using 2,500 litres a week, or 10,000 litres over four weeks.

At September’s closing average, those 10,000 litres would cost $26,070. That is $2,390 more than at August’s closing average, and $10,760 more than at the previous September’s closing average.

These are comparisons using closing prices, rather than a calculation of what a carrier actually spent during September.

At that volume, every cent saved per litre is worth $100 over four weeks. A 5-cent saving would mean $500 before fees. A 10-cent saving would mean $1,000.

That is useful money. But the discount only counts if it applies where you actually buy fuel.

Retail-minus or cost-plus?

With retail-minus, your agreement subtracts a discount from a defined retail price. Ask which price: the posted pump price, a particular payment price or another reference.

With cost-plus, your agreement adds a markup to a defined cost or wholesale benchmark. Ask which benchmark applies, when it updates and what else is added.

Neither formula always wins.

If retail rises faster than the cost-plus benchmark, cost-plus can become more favourable. If wholesale prices rise quickly while retail prices lag, that advantage can shrink or disappear.

September also showed why “cost-plus” does not mean protection from a price spike. Kalibrate reported a record diesel refining margin of 142.2 cents a litre on September 21. That margin measures the spread between crude and wholesale diesel prices; it is not the retailer’s margin or the refiner’s net profit. Higher wholesale prices can flow through to cost-plus customers.

The useful comparison is the final price each agreement would charge at the same station on the same day.

Payment terms deserve a place in the calculation

At September’s closing retail average, 2,500 litres would cost about $6,518.

On prepaid terms, you need available funds before fuelling. Higher prices mean topping up more money to buy the same litres.

A credit account, subject to approval and its limits, lets you pay later under agreed terms. That can help cash flow, but the bill still comes due. Check the billing cycle, payment date, security requirements and late-payment charges.

Choose terms your business can reliably support.

Controls help you manage purchases

Depending on the program, you may be able to restrict products, spending, purchase times or approved locations.

Those controls can reduce unauthorized purchases and help drivers follow your fuelling plan. They still need sensible limits and regular review. A diesel-only restriction, for example, cannot distinguish a tractor’s tank from a diesel pickup’s tank.

Detailed invoices can also simplify recordkeeping. For IFTA, however, you still need distance records by jurisdiction and acceptable fuel-purchase documentation. A provincial purchase summary alone is insufficient. Ontario’s requirements distinguish qualifying detailed invoices or transaction listings from supplier statements.

Check the saving after fees

A $2 transaction fee on a 400-litre fill costs half a cent per litre. The same fee on a 100-litre fill costs two cents per litre.

Before signing, ask:

• Which stations accept the card, and where does the quoted pricing apply?
• What exact price or benchmark is used?
• Which transaction, account or other fees apply?
• Can you see prices before choosing a stop?
• Can you verify the calculation on your invoice?

Then compare actual fills, including fees and any extra driving needed to reach a discounted station.

A fuel card cannot control the diesel market. It can help you manage what you pay, where your drivers buy and when payment leaves your account. Those benefits are worth measuring against your own routes and fuel bills.

If you want help checking the numbers, ZyloFuel’s free fuel bill check is a place to start.