Monthly fuel cost depends on how far you drive, your vehicle’s fuel consumption and the price you pay per litre. Because fuel prices change, a formula using your own current price is more useful than a fixed national dollar estimate.
Use Distance, Fuel Economy and Price
Estimate monthly kilometres, multiply by your vehicle’s litres per 100 km, divide by 100, then multiply by the fuel price per litre. This produces a practical fuel-only estimate.
| Input | Example |
|---|---|
| Monthly distance | 1,500 km |
| Fuel economy | 8 L/100 km |
| Fuel used | 120 L/month |
| At $1.60/L | $192/month |
Estimate Your Monthly Driving
Include commuting, errands and regular weekend trips. If you know weekly kilometres, multiplying by 52 and dividing by 12 gives a useful monthly average.
Use Your Vehicle’s Real-World Consumption
Published fuel economy can be a starting point, but weather, traffic, driving style and short trips can change consumption. If your dashboard provides a long-term average, it may better reflect your actual use.
Test More Than One Fuel Price
Fuel prices move. Calculate a normal-price scenario and a higher-price scenario to see how sensitive your monthly budget is.
Remember That Fuel Is Only One Car Cost
Insurance, maintenance, parking, financing and depreciation can be larger than fuel for some drivers. Use the fuel estimate as one part of your transportation budget.
A Simple Way to Check Your Numbers
Start with your normal month, then test a higher-cost scenario. This helps you see whether the plan still works when fuel, groceries, housing or another variable expense changes. Keep the assumptions visible so you can update the calculation later rather than rebuilding the budget from scratch.
Frequently Asked Questions
What formula estimates monthly gas cost?
Monthly km × L/100 km ÷ 100 × price per litre.
Should I use highway or city fuel economy?
Use a blended number that best matches your real driving, or your vehicle’s long-term average if available.
Does this include maintenance?
No. It estimates fuel only.
This information is general and may change. Check the linked official source for rules that apply to your situation.
