Estimate how much fuel a trip will use and what it will cost, based on distance, fuel efficiency and fuel price — in Metric or US units.
Enter your trip details and click Calculate
This fuel cost calculator estimates how much fuel a trip will burn and what it will cost, using just three numbers — distance, fuel efficiency, and fuel price. It works as both a metric fuel cost calculator (km, liters per 100km) and a US gas cost calculator (miles, MPG, price per gallon), switching the underlying formula automatically depending on which unit system you select, so it's useful anywhere in the world.
In Metric mode, fuel needed is Distance (km) ÷ 100 × Efficiency (L/100km), then multiplied by the price per liter for the total cost. In US mode, fuel needed is Distance (miles) ÷ Efficiency (MPG), multiplied by the price per gallon. Checking "round trip" simply doubles the distance before either calculation runs, so you can enter the one-way distance and still get an accurate there-and-back total. The results panel also shows cost per mile or per km, letting you compare trips or vehicles on an even footing.
This tool suits anyone who wants a fast, no-signup answer to "what will this trip cost in fuel?" — road-trippers planning a route, commuters estimating a weekly or monthly gas budget, rideshare and delivery drivers tracking a real cost against their earnings, people comparing two vehicles before a purchase, and anyone estimating mileage reimbursement for work travel. It works equally well for a short daily commute or a multi-day cross-country drive.
Fuel is one of the largest variable costs of driving, and it's easy to underestimate on a long trip — especially when converting between L/100km and MPG, which move in opposite directions (lower is better for one, higher is better for the other). A quick fuel cost estimate helps with road trip budgeting, comparing vehicles before a purchase, or working out mileage reimbursement for work travel.
The exact math behind the Metric and US modes of this fuel cost calculator
The calculator applies whichever formula matches your selected unit system — it never mixes L/100km with a per-gallon price or MPG with a per-liter price. Round trip, when checked, doubles the distance before either formula runs, so fuel needed, total cost, and cost per distance all reflect the full there-and-back trip.
L/100km already expresses fuel use per 100 units of distance, so the distance must be scaled down to "hundreds of km" before multiplying by the efficiency figure.
MPG expresses distance covered per unit of fuel, so dividing total distance by MPG directly yields the gallons of fuel needed — no scaling step required.
Doubling happens before the fuel and cost formulas run, so you only ever need to enter the one-way distance and check the box.
From entering your trip details to reading your fuel cost estimate
Select Metric (km, L/100km, price per liter) or US (miles, MPG, price per gallon) depending on which units you know your trip and vehicle figures in.
Type the one-way distance you plan to drive, in kilometers or miles depending on your selected unit system.
Enter your vehicle's L/100km or MPG rating. A recent, real-world figure from your trip computer or fill-up log gives a more accurate result than the factory-rated figure.
Pick a currency symbol, enter the current price per liter or per gallon, and check the round-trip box if you want the distance doubled automatically.
See your total fuel needed, total trip cost, and cost per mile or per km appear instantly in the results panel.
One Metric and one US example, worked out step by step
Suppose you're driving 300 km one way, your car averages 7.5 L/100km, and fuel costs $1.50 per liter, with no round trip.
Suppose you're driving a 300-mile round trip (150 miles each way entered as the one-way distance, with round trip checked), your car averages 28 MPG, and gas costs $3.50 per gallon.
Explanation: Both scenarios reduce to the same two steps — work out fuel needed from distance and efficiency, then multiply by the price to get total cost. Notice the round-trip example simply doubles the one-way distance first; everything downstream (fuel needed, cost, and cost per mile) is calculated on that doubled figure, which is why entering the one-way distance and checking the box gives the same answer as manually typing in the full 300-mile round-trip distance.
What Total Fuel Needed, Total Cost, and Cost per Mile/km actually tell you
Total Fuel Needed is how much fuel (in liters or gallons) your trip is estimated to use, based on the distance and efficiency you entered. It's useful for planning how many fill-ups a longer trip might need, or for checking whether your tank capacity is enough to cover the distance without stopping.
Total Cost is the headline budgeting number — what you can expect to spend on fuel for the trip at the price you entered. Use it to build a road-trip budget, estimate a weekly or monthly commuting cost by multiplying by the number of trips, or set aside funds before a delivery or rideshare shift.
Cost per Mile/km strips distance out of the equation entirely, giving you a rate you can use to compare trips of different lengths, compare two vehicles on equal footing, or multiply against any other distance to estimate its fuel cost without recalculating from scratch.
This calculator provides an estimate based on the figures you supply. Real-world fuel cost can vary with traffic, terrain, weather, driving style, and fuel-price changes between when you calculate and when you actually drive.
Where a quick, accurate fuel cost estimate is genuinely useful
Estimate total fuel spend for a multi-day drive before you set off, so you can budget alongside lodging and food.
Work out your one-way commute cost, then multiply by your weekly or monthly driving days for a running total.
Run the same trip distance through two different efficiency figures to see the fuel-cost gap between two cars.
Estimate fuel cost per shift and compare it against your earnings using the cost-per-mile/km figure.
Quickly estimate the fuel-only cost of a planned route for a single vehicle before dispatching it.
Factor fuel cost into a moving-truck or personal-vehicle relocation budget alongside other moving costs.
RVs typically have poor fuel efficiency — get a realistic total before committing to a route.
Enter a gas vehicle's and a hybrid's MPG for the same trip to see the fuel-cost difference side by side.
Get a rough fuel-only figure to sanity-check against your employer's per-mile reimbursement rate.
Calculate the trip's total fuel cost, then divide it evenly among riders for a fair contribution.
Estimate fuel cost for a rental car trip or an airport drop-off before you return the keys.
Log fuel cost per job or delivery run to understand your true per-trip profit margin.
What this fuel cost calculator does well, and where its estimate has boundaries
Rough real-world ranges to sanity-check the efficiency figure you enter
| Vehicle Type | Typical L/100km | Typical MPG (US) |
|---|---|---|
| Compact / subcompact car | ~5.5 – 6.5 | ~36 – 43 |
| Midsize sedan | ~7.0 – 8.0 | ~29 – 34 |
| Hybrid sedan | ~4.0 – 5.0 | ~47 – 59 |
| Compact SUV / crossover | ~7.5 – 9.0 | ~26 – 31 |
| Full-size SUV | ~10.0 – 12.0 | ~20 – 24 |
| Pickup truck | ~11.0 – 13.0 | ~18 – 21 |
| Minivan | ~8.5 – 10.0 | ~24 – 28 |
| RV / motorhome | ~19.0 – 25.0 | ~9 – 12 |
These are rough real-world ranges, not manufacturer-rated figures — actual efficiency depends heavily on the specific model, engine, load, and driving conditions. Use them only as a sanity check if you don't yet know your own vehicle's figure; your trip computer or a recent fill-up log will always be more accurate.
Summary: This fuel cost calculator gives you an instant, free estimate of trip fuel needed, total cost, and cost per mile/km in Metric or US units, with a one-click round-trip toggle — a solid planning figure, not a guaranteed price. Pair it with the Fuel Efficiency Converter and Trip Cost Calculator for a fuller picture of your trip's total budget.
Common questions about estimating trip fuel cost
Official guidance to complement this calculator — not a substitute for vehicle-specific ratings
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