Use this fuel expense calculator for a one-way drive, round trip, road trip, or several identical journeys.
Enter the distance, your vehicle's real fuel economy, and the current price at the pump or charger.
The result includes fuel or electricity used, total driving cost, cost per mile or kilometer, and an
equal cost per person when you are sharing the ride. Include tolls, parking, and other charges for a
more complete car trip cost calculator estimate.
1. Add the distanceUse miles or kilometers and switch on round trip when needed.
2. Add efficiencyChoose the exact MPG, L/100 km, km/L, or EV unit your vehicle uses.
3. Add and split costsInclude tolls, parking, and other costs before dividing the total.
Fuel Consumption Calculator and Supported Units
Use the tool as a fuel consumption calculator or fuel usage calculator when you want to estimate
the gallons, liters, or kWh needed for a journey—not only the price. Choose the units that match
your vehicle and local fuel or electricity price.
Distance: miles and kilometers
Fuel economy: MPG (US), MPG (UK), miles/L, km/L, and L/100 km
EV efficiency: miles/kWh, km/kWh, kWh/100 mi, and kWh/100 km
Energy price: per US gallon, imperial gallon, liter, or kWh
Gasoline, Gas, and Travel Cost Estimates
Gasoline trip budgets
For a gasoline vehicle, this gasoline cost calculator divides distance by fuel economy, then
multiplies the gallons used by the price at the pump. The same inputs make it a practical gas cost
calculator or gas expense calculator for commutes, road trips, deliveries, and carpools. To
calculate gas cost for trip planning, use the expected route distance and an MPG figure that
reflects how and where you will drive.
Total driving and travel costs
Because the tool can add tolls and parking, split passengers, and project repeated journeys, it
also works as a driving cost calculator or travel fuel cost calculator. The fill-up helper makes
it a useful car fuel calculator too: enter distance driven and fuel used to estimate your own
real-world MPG, km/L, or L/100 km before calculating the next trip.
Calculate Commute Cost
To estimate the cost of driving to work, enter the route as one round trip or enter the one-way
distance and switch on Round trip. Under More options, turn on
Regular commute, then enter how many days you drive each week and how many weeks
you work each year. The result shows weekly, average monthly, and annual commute cost. Parking,
bridge fees, and road tolls can be included before the projection, so the estimate reflects more
than gas alone.
Split Fuel Cost Between Passengers
Switch on Split the cost and enter the total number of people in the car, including
the driver if the driver is paying a share. The calculator adds fuel or charging cost and any extras,
then divides the full amount equally. This makes it useful as a road trip gas split calculator, a
carpool cost calculator, or a quick way to work out fair gas money for passengers.
Calculate EV Charging Cost
Choose Electric, enter your EV's efficiency, and add the electricity price per kWh.
You can use miles per kWh or kilometers per kWh when your dashboard shows distance per unit of
energy. If it shows consumption, choose kWh/100 miles or kWh/100 km instead. An optional charging
loss percentage is available under More options. Leave it at 0% when you want the
battery-use estimate only, or add a measured loss when you want a closer estimate of energy drawn
from the charger.
What Affects Your Car's Fuel Consumption?
Your vehicle's official MPG, km/L, or L/100 km rating is a useful baseline, but real fuel consumption
and driving range change from one journey to another. The car must overcome rolling resistance, air
resistance, hills, repeated acceleration, and power used by accessories. For the most realistic
estimate, use an efficiency figure measured on recent trips in conditions similar to the journey you
are planning.
Speed, acceleration, and braking
Rapid acceleration, hard braking, and speeding waste energy. Fuel economy usually falls quickly
above 50 mph because aerodynamic drag rises with speed. Smooth inputs, anticipation, and a steady
legal speed generally reduce consumption; cruise control can help on suitable, fairly level roads.
Tire pressure and rolling resistance
Underinflated tires flex more and increase rolling resistance. Check them when cold and use the
pressure on the driver's-door label or in the owner's manual—not the maximum printed on the tire.
Wheel misalignment, dragging brakes, and some high-resistance tire designs can also use more fuel.
Temperature and short journeys
A cold engine, transmission, battery, and tires operate less efficiently. Short trips are hit
hardest because the vehicle spends more of the journey warming up. In hot weather, air conditioning
adds load; in cold weather, heating and defrosting can noticeably reduce an EV's range.
Wind and aerodynamics
A strong headwind increases the air resistance the car must overcome, while a tailwind may reduce
it. Roof racks, roof boxes, bicycles, open windows at highway speed, and other items outside the
vehicle disturb airflow. Their effect becomes larger as driving speed increases.
Traffic, idling, and route choice
Stop-and-go traffic repeatedly turns fuel into acceleration and then loses that energy through
braking. Idling covers no distance while still using fuel. A slightly longer route at a steady
speed can sometimes use less than a congested route, and combining short errands avoids several
inefficient cold starts.
Hills, roads, and weather
Climbing requires extra energy, and the descent does not always recover all of it. Mountain roads,
gravel, mud, standing water, snow, and ice can increase resistance or wheel slip. Heavy rain and
poor conditions may also force repeated speed changes that make the original estimate less accurate.
Weight, towing, and four-wheel drive
Extra passengers, luggage, and cargo require more energy whenever the car accelerates or climbs.
Towing adds weight and substantial aerodynamic drag. Engaging four-wheel drive can add mechanical
losses, while a loaded roof box affects both weight and airflow.
Maintenance, oil, and fuel blend
Engine faults, incorrect oil, poor wheel alignment, and dragging brakes can reduce efficiency.
Follow the manufacturer's service schedule and investigate warning lights. Gasoline energy content
also varies with ethanol content and seasonal fuel blends, so identical trips may not always return
identical fuel usage.
The calculation first converts the selected distance and efficiency into fuel or electricity used.
It keeps full precision through every step and rounds displayed money to two decimal places. Tolls,
parking, and other expenses are added only after the energy cost is calculated.
Fuel used = distance ÷ fuel economy
Fuel cost = fuel used × price per gallon or liter
Total trip cost = fuel cost + tolls + parking + other costs
Cost per person = total trip cost ÷ total people sharing
For L/100 km, the tool uses liters = kilometers × L/100 km ÷ 100. For an EV rated in kWh/100 km,
it uses kWh = kilometers × kWh/100 km ÷ 100. A round trip doubles distance before fuel use is
calculated; the number-of-trips option then multiplies the complete journey.
US vs Imperial Gallons
A US gallon and a UK imperial gallon are not the same size. One US gallon equals 3.785411784 liters,
while one imperial gallon equals 4.54609 liters. That difference also means a UK MPG figure cannot be
entered as MPG (US) without changing the result. Choose MPG (US) for US vehicle data
and fuel sold per US gallon. Choose MPG (UK) for an imperial MPG rating; the calculator
then converts fuel use through imperial gallons and lets you pair it with price per imperial gallon or
price per liter. The explicit labels are there to prevent one of the most common fuel-cost errors.
MPG, L/100 km, and km/L Explained
Unit
What it means
How to read it
MPG (US)
Miles traveled per US gallon
A higher number means better fuel economy.
MPG (UK)
Miles traveled per imperial gallon
Use only with an imperial MPG rating.
L/100 km
Liters used to travel 100 kilometers
A lower number means better fuel economy.
km/L
Kilometers traveled per liter
A higher number means better fuel economy.
mi/kWh
Miles traveled per kilowatt-hour
A higher number means a more efficient EV.
kWh/100 km
Electricity used over 100 kilometers
A lower number means a more efficient EV.
Fuel Cost Calculator Examples
Weekend road trip with friends
A 300-mile round trip at 30 MPG uses 10 US gallons. At $3.50 per gallon, fuel is $35. Add $15 in tolls and split between four people: $12.50 each.
Daily gasoline commute
A 24-mile round trip at 32 MPG uses 0.75 gallon per workday. At $3.60 per gallon, that is $13.50 per five-day week before parking or tolls.
European motorway trip
A car rated at 6.5 L/100 km uses 32.5 liters over 500 km. At €1.80 per liter, fuel costs €58.50 before motorway tolls.
EV charged at home
An EV using 18 kWh/100 km needs 36 kWh for 200 km. At €0.30 per kWh, charging costs €10.80 before an optional charging-loss adjustment.
Diesel van delivery
A 180-mile delivery at 24 MPG (US) uses 7.5 gallons. At $3.90 per gallon, estimated diesel cost is $29.25.
One way vs. round trip
If a 100-mile one-way drive costs $18, switching on round trip uses 200 miles and makes the equivalent estimate $36, assuming the same conditions.
Frequently Asked Questions
How do I calculate fuel cost for a trip?
Divide the trip distance by your vehicle's fuel economy to find fuel used, then multiply by the price per gallon or liter. Add tolls, parking, and other trip costs afterward.
How much gas will my trip cost?
Enter the route distance, MPG, and current gas price in the calculator. It returns gas needed, gas cost, and total trip cost immediately.
How do I calculate gas cost per mile?
Divide total gas and trip expenses by the total miles driven. The result panel calculates this automatically as cost per distance.
How do I split gas cost between passengers?
Add all shared driving expenses, switch on Split the cost, and enter the total people paying. The tool divides the full amount equally.
Does the driver count in the gas split?
Yes, if the driver is paying a share. Enter everyone who contributes, including the driver. Leave the driver out only when the group has agreed the driver pays nothing.
How do I calculate round-trip fuel cost?
Enter the one-way distance and switch on Round trip. The calculator doubles the distance before calculating fuel use and cost.
How do I calculate weekly, monthly, or annual commute cost?
Set up one commute day, turn on Regular commute, and enter commute days per week and working weeks per year. The result shows all three periods.
What is the difference between MPG (US) and MPG (UK)?
MPG (US) uses a 3.785-liter US gallon. MPG (UK) uses a 4.54609-liter imperial gallon, so the same numeric MPG value represents different fuel use.
How do I convert MPG to L/100 km?
For US MPG, divide 235.214583 by MPG. For example, 30 MPG (US) is about 7.84 L/100 km.
How do I calculate petrol or diesel trip cost in liters?
Choose kilometers and liters, enter km/L or L/100 km, then enter the petrol or diesel price per liter. The fuel type does not change the formula.
How do I calculate EV charging cost for a trip?
Calculate the kWh needed from distance and EV efficiency, then multiply by electricity price per kWh. Add charging loss only when you want to estimate energy drawn from the charger.
Can I add tolls and parking?
Yes. Put all additional shared driving expenses in the tolls, parking, and other costs field. They are added once per complete calculation.
Should I enter one-way or round-trip distance?
Enter the distance you already know. If it is one way and you will return, switch on Round trip. Do not switch it on when your entered distance already includes both directions.
Is the result exact?
No. It is an estimate based on your inputs. Traffic, speed, weather, elevation, cargo, tire pressure, charging losses, and driving style can change real consumption.
What affects fuel consumption most on a road trip?
Speed and driving style can have a large effect, especially at highway speeds. Headwinds, tire pressure, roof cargo, vehicle weight, hills, temperature, traffic, air conditioning, and maintenance can also change real fuel use and range.
Why is my actual trip cost higher than the estimate?
Your real MPG may be lower than the value entered because of traffic, cold starts, high speed, wind, hills, low tire pressure, extra weight, or climate-control use. Recalculate with fuel economy measured from a recent similar trip for a closer estimate.
Method and review: Calculations use 1 mile = 1.609344 km, 1 US gallon =
3.785411784 L, and 1 imperial gallon = 4.54609 L. The page keeps full internal precision and
rounds displayed money to two decimals. Methodology reviewed by the Fuel Cost Calculator
editorial team. Last updated July 20, 2026. For a separate official US trip-cost reference, see
FuelEconomy.gov.
