Fuel Cost Calculator
Work out how much a trip will cost you in fuel.
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"How much will this road trip actually cost in gas?" is one of those questions everyone estimates badly, usually on the low side. Plug in your distance and your car's real consumption, and this calculator gives you a number worth planning around.
How the estimate is calculated
In metric mode: (distance ÷ 100) × consumption (L/100km) × price per liter. In imperial mode: (distance ÷ mpg) × price per gallon. Both reduce to the same idea — how much fuel the trip burns, multiplied by what that fuel costs.
A worked example
Say you're driving 450 km, your car averages 6.5 L/100km, and fuel costs 1.85 per liter. The trip burns (450 ÷ 100) × 6.5 = 29.25 liters. At 1.85 per liter, that's 29.25 × 1.85 = 54.11 total. In imperial terms, the same idea applies to a 280-mile trip in a car rated at 32 mpg with fuel at 3.60 per gallon: 280 ÷ 32 = 8.75 gallons, and 8.75 × 3.60 = 31.50 total. The calculator above does exactly this arithmetic instantly for your own numbers.
Manufacturer figures vs. real-world consumption
The consumption figure on a car's spec sheet is measured under controlled lab conditions, and real-world driving is rarely that kind. Highway cruising at a steady speed gets closer to the official number; city driving, hills, cold weather, air conditioning, and a heavy load can all push actual consumption 15–30% higher than the rated figure. If you know your car's real average from past fill-ups (trip miles ÷ gallons used, or the equivalent in liters/km), that number will give you a far more accurate estimate than the number from the brochure.
Practical ways to use this
- Budgeting a road trip before you leave, so there are no surprises.
- Comparing two routes — a shorter route with more stop-and-go traffic can sometimes cost more in fuel than a longer, steadier one.
- Splitting costs fairly with passengers on a shared trip.
- Comparing a gas car's running cost against an EV's estimated electricity cost for the same trip, if you're weighing a purchase.
Frequently asked questions
Why does the result differ from what I actually spent last time?
Real driving conditions vary trip to trip — traffic, terrain, weather, and driving style all affect actual consumption more than most people expect. Treat this as a solid estimate, not an exact prediction.
What currency does this use?
None specifically — enter the price per liter or gallon in whatever currency you use locally, and the result comes back in that same currency.
How do I find my car's L/100km or mpg figure?
Check your vehicle's manual or manufacturer spec sheet for the official rating, or calculate your own from a recent fill-up: distance driven since the last full tank, divided by the fuel used to fill it back up.
Does this account for tolls or other trip costs?
No — this calculates fuel cost only. For a full trip budget, add tolls, parking, and other expenses separately.
Does this work for electric vehicles?
Not directly — it's built around liters/gallons of fuel. For an EV, compare cost per trip using your electricity rate and the car's efficiency rating in kWh per 100 km or per mile instead.
Why does my result differ from a trip-planning app's estimate?
Those apps often assume a generic manufacturer consumption figure and may use outdated regional fuel prices. This calculator uses exactly the numbers you enter, so it's only as accurate as your own inputs — which is usually more accurate for your specific car.