⛽ Fuel Cost Calculator
Estimate what a drive really costs in gas: total fuel cost, cost per person and cost per mile — great for planning road trips and splitting expenses.
How to use the Fuel Cost Calculator
Enter distance, fuel efficiency and price per unit to see trip cost, cost per kilometre and annual cost at a given annual mileage.
How it works
Cost per distance is simply price per unit divided by efficiency, giving cost per kilometre or mile. Annual cost multiplies that by your annual distance. Comparing vehicles on cost per kilometre is often more informative than comparing total ownership cost, and the gap between an efficient and an inefficient car compounds quickly over high annual mileage.
When to use it
Use it to work out whether a vehicle upgrade pays for itself on fuel, to plan a long trip budget, or to compare real-world efficiency against the manufacturer rating.
Worked example
Two mid-size cars compared:
| Vehicle | Efficiency | Cost/km | Annual (20,000 km) |
|---|---|---|---|
| Small hatchback | 7.0 L/100km | $0.086 | $1,720 |
| Mid-size sedan | 9.5 L/100km | $0.117 | $2,340 |
| Hybrid | 4.5 L/100km | $0.055 | $1,100 |
Assumptions and limitations
Official efficiency ratings are measured on standardised cycles that rarely match real driving, where cold starts, city traffic and highway speed all change the result. Fuel prices vary by region and over time. Insurance, maintenance, depreciation and registration are excluded and often exceed fuel cost over ownership. Not financial advice.
Frequently Asked Questions
How do I calculate the fuel cost of a trip?
Fuel cost = (distance ÷ MPG) × price per gallon. For example, a 300-mile drive at 28 MPG with gas at $3.20/gal needs about 10.7 gallons, or roughly $34 — double it for a round trip.
Should I use my car's rated MPG?
Window-sticker MPG assumes mixed driving. Steady highway cruising usually beats the rating, while city stop-and-go falls below it. For a road trip the rated number is a good starting point; for city driving, knock off 15–25%.
What gas price should I enter?
Use the price where you will actually fill up — US prices vary a lot by state and even by neighborhood. Checking a local station or a national daily average (such as AAA's) gives you the most realistic budget.
How do I split gas costs fairly between passengers?
The simplest fair split is the total fuel cost divided by everyone in the car — that's what the "people splitting the cost" field does. Keep in mind fuel is only part of a trip's cost: tolls, wear and tear run roughly $0.15–$0.30 per mile extra.
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