Written by Sarah Mitchell · Reviewed by Alex Chen · July 25, 2026
Estimate your trip fuel costs based on distance, fuel efficiency, and fuel price.
Enter values and click Calculate.
This calculator turns a planned distance, your vehicle's fuel economy, and the local fuel price into the volume of fuel the trip will burn, the total cost, and the cost per kilometer or mile. It works in metric units, where economy is kilometers per liter, and in imperial units, where it is miles per gallon. All computation is client-side, so nothing you type is transmitted.
In metric mode, litersNeeded = distanceKm / efficiencyKmPerL. That volume is multiplied by the price per liter to get the total cost, and the cost divided by the distance gives the per-kilometer figure. The imperial path mirrors it exactly: gallonsNeeded = distanceMi / efficiencyMpg, then cost = gallons x pricePerGallon.
Suppose you drive 620 km in a car that averages 12.4 km per liter. Dividing gives 620 / 12.4 = 50 liters. At $1.85 per liter the fuel costs 50 x 1.85 = $92.50, which is about $0.15 per kilometer. In imperial terms, a 300-mile drive at 30 mpg uses 300 / 30 = 10 gallons, and at $3.50 per gallon that comes to $35.00, roughly $0.12 per mile.
The formula assumes a constant economy, but real fuel consumption swings with traffic, payload, air conditioning, tire pressure, winter fuel blends, and highway speed. Short trips and cold starts burn extra fuel before the engine warms up. The estimate is a planning number built from the efficiency you enter; feed it a realistic figure, ideally from your trip computer or a few fill-ups, and the result will be far closer.
Use the system your car's display and your local fuel pumps use. Kilometers per liter is standard in most of the world; miles per gallon is common in the United States.
The trip computer is the easiest source. Otherwise, note the distance between two fill-ups and divide it by the liters or gallons added in the second fill-up.
No. It covers fuel alone. Add tolls and parking separately when building a complete trip budget.
Not directly, since the inputs are volume and price per liter or gallon. For an EV, compare kilowatt-hours instead, using your car's consumption per 100 km.
It is the number that stays comparable when distances change. Total cost rises with distance, but the per-kilometer figure lets you compare two vehicles or two routes fairly.
Enter the price at the station you plan to use, or the average of the last few stations. A small difference in price shifts the total by a few cents per kilometer.
Use it before a long drive to budget the tank, when comparing a fuel-hungry vehicle against an efficient one, or when splitting travel costs among passengers. Skip it when you need the full cost of ownership, including insurance, depreciation, and maintenance, because fuel is only one slice of that picture.
The results panel reports volume, total cost, and cost per unit of distance, and each number answers a separate question. Volume says how many liters or gallons the trip will burn, which is the figure you watch at the pump. Total cost is that volume multiplied by the current price, useful for a single journey. Cost per kilometer or mile is the total divided by the distance, and it holds steady no matter how far you drive, which makes it the clearest basis for comparing vehicles.
For a round trip or a route with a detour, work in stages. Enter the outbound distance, note the total, then enter the return leg and note that total again; adding the two figures gives the full journey cost. If the route mixes dense city streets with open highway, average the economy between your city figure and your highway figure rather than using either extreme, because the real consumption lands somewhere in between.
The estimate covers fuel alone. It ignores overnight stays, meals, toll bridges, and the extra draw of a loaded roof box or trailer. Cold weather adds a few percent to real usage before the engine reaches temperature, and idling in traffic burns fuel without adding distance. Treat the figure as the lower bound of the trip's running cost, then add a comfortable buffer for the conditions a simple division cannot account for.
The unit switch at the top of the panel flips the entire form: the metric side shows kilometers, kilometers per liter, and a price per liter, while the imperial side shows miles, miles per gallon, and a price per gallon. Toggling the choice recalculates instantly with the values already in place. The metric and imperial forms never mix: the result labels always match the side you last selected, so a liter figure cannot appear on a mile-based trip. The page keeps no memory of your inputs across visits, so jot down any number you want to keep before closing the tab.
Leaving a field empty is treated as zero: a blank distance yields a zero total cost, and a blank price produces a zero bill even when the distance is entered. The economy inputs refuse anything below one tenth, so the division that computes fuel needed never divides by a tiny or vanishing number. Those guardrails keep every result finite and readable.
The result panel lists the distance, the economy, the fuel needed, the price, and the cost per kilometer or mile. The big headline is the total bill rounded to two decimals, while the per-unit figure shows three decimals so the comparison between routes stays precise even on short drives. Reading all five rows together gives the full picture behind the headline number.