Estimate fuel cost for a trip or commute from distance, fuel economy, and pump price. See gallons or liters needed, cost per mile, round-trip cost, and optional per-person split.
Fuel Cost Calculator
Choose a mode, enter your values, and press Calculate for an instant estimate.
US mode means US miles per US gallon. This calculator does not convert to or from Imperial (UK) gallons. The currency symbol is for display only; it does not convert currencies.
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Optional: Split Cost and Tank Size
Shows an approximate number of tanks the fuel would take. This does not assume your tank starts empty.
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Optional: Projected Annual Savings
If your comparison distance above is not already your annual mileage, enter it here to project a yearly savings based on the cost-per-distance difference found above.
This is a fuel-only estimate. It does not include insurance, maintenance, tires, depreciation, parking, or tolls.
Want to find your vehicle's real MPG from actual fill-ups instead of an estimate? Use the Gas Mileage Calculator.
A fuel cost estimate needs three basic pieces of information: distance, fuel economy, and fuel price. For a vehicle measured in US miles per gallon, gallons needed equal distance divided by MPG. Fuel cost then equals gallons needed multiplied by the price per gallon.
Suppose a trip is 300 miles, your vehicle gets 30 MPG, and fuel costs $3.50 per gallon. Fuel needed is 300 divided by 30, which equals 10 gallons. Cost is 10 times $3.50, which equals $35. So the estimated fuel cost is $35.
Visual: Trip Cost Formula
Distance divided by MPG gives gallons needed. Gallons needed multiplied by pump price gives fuel cost.
Steps used to turn distance into fuel cost
Step
Calculation
Gallons needed
Distance divided by MPG
Fuel cost
Gallons needed multiplied by pump price
That is the core math behind the Fuel Cost Calculator.
What About a Round Trip?
A round trip includes the outbound and return distance. If the destination is 150 miles away, the round-trip distance is 150 times 2, which equals 300 miles.
Visual: Round Trip Distance
150 miles out plus 150 miles back equals 300 effective miles. The calculator always displays this effective distance so you can see whether the round-trip toggle doubled the mileage.
How a one-way distance becomes an effective round-trip distance
Segment
Distance
Outbound
150 miles
Return
150 miles
Effective total
300 miles
At 30 MPG, 300 divided by 30 equals 10 gallons. At $3.50 per gallon, 10 times $3.50 equals $35. The calculator always displays the effective distance so the user can see whether the round-trip toggle doubled the mileage.
How Much Gas Do I Need for 500 Miles?
The answer depends on fuel economy. At 20 MPG, 500 divided by 20 equals 25 gallons. At 25 MPG, 500 divided by 25 equals 20 gallons. At 40 MPG, 500 divided by 40 equals 12.5 gallons. That is why a generic statement such as "a 500-mile trip uses 20 gallons" cannot be correct for every vehicle. Enter your own expected MPG above for the closest estimate.
How Do I Find My Vehicle's MPG?
If you do not know your vehicle's fuel economy rating, the official U.S. FuelEconomy.gov resource provides EPA fuel economy information by vehicle. EPA labels commonly show city MPG, highway MPG, and combined MPG. Use the number that best matches the kind of driving you expect. For mixed driving, combined MPG can be a reasonable planning starting point. For a long highway trip, actual highway fuel economy may differ from combined MPG, and your real mileage can also differ from the label.
Why Does Real MPG Differ From the EPA Number?
EPA explains that actual fuel economy can vary. Factors can include speed, acceleration, weather, air conditioning, road conditions, traffic, vehicle load, maintenance, tires, and terrain. That means this calculator is an estimate. If you track your own real-world MPG using the CalculateThisWay Gas Mileage Calculator, that measured average may provide a better input for planning your personal trip.
Fuel Cost Per Mile
Fuel cost per mile is fuel cost divided by distance. Using the 300-mile example, $35 divided by 300 equals about $0.1167 per mile, or about 11.7 cents of fuel per mile. This is fuel cost only. It does not include insurance, maintenance, tires, depreciation, parking, or tolls. Do not label fuel cost per mile as the vehicle's total cost of ownership.
Gallons Per 100 Miles
MPG tells you how far a vehicle travels per gallon. Fuel consumption tells you how much fuel it uses over a set distance. EPA fuel labels include gallons per 100 miles because fuel consumption is directly related to fuel cost. The formula is gallons per 100 miles equals 100 divided by MPG. At 20 MPG, 100 divided by 20 equals 5 gallons per 100 miles. At 25 MPG, that is 4 gallons. At 50 MPG, that is 2 gallons.
Visual: MPG vs. Gallons Per 100 Miles
As MPG rises, gallons used per 100 miles falls, but not in a straight line. This also shows why MPG is nonlinear.
MPG compared with gallons used per 100 miles
MPG
Gallons per 100 Miles
20 MPG
5 gallons
25 MPG
4 gallons
50 MPG
2 gallons
Going from 10 MPG to 20 MPG saves far more fuel over a fixed distance than going from 40 MPG to 50 MPG.
Why a 5-MPG Improvement Is Not Always the Same
Suppose two vehicles each improve by 5 MPG. Vehicle 1 goes from 15 MPG to 20 MPG. Vehicle 2 goes from 35 MPG to 40 MPG. The numerical improvement is five MPG in both cases, but gallons saved over the same distance are not equal.
For a 100-mile drive: 15 MPG uses 6.67 gallons, and 20 MPG uses 5 gallons, a difference of about 1.67 gallons. 35 MPG uses about 2.86 gallons, and 40 MPG uses 2.5 gallons, a difference of about 0.36 gallon. This is sometimes called the MPG illusion. Fuel consumption per 100 miles makes the difference easier to see.
How Do I Calculate Fuel Cost in L/100 km?
Many countries describe fuel consumption as liters per 100 kilometers. Liters needed equal distance in kilometers times L/100 km, divided by 100. Suppose a trip is 500 km at 8 L/100 km. Fuel is 500 times 8 divided by 100, which equals 40 liters. If fuel costs 1.70 per liter, then 40 times 1.70 equals 68 currency units. The arithmetic is the same regardless of currency because the user supplies the price.
What Is km/L?
Kilometers per liter expresses distance traveled for each liter. Liters used equal distance divided by km/L. Higher km/L means better fuel economy. This behaves more like MPG than L/100 km, so do not interchange the numbers directly.
How Do I Split Gas Money?
If several people agree to share fuel evenly, cost per person equals total fuel cost divided by number of people. For example, a fuel cost of $84 split three ways is $84 divided by 3, which equals $28 each. The calculator calls this an equal fuel-cost split. It does not decide whether the driver should pay a share or whether other expenses should be included. That is up to the people traveling.
How Much Does My Commute Cost?
A commute calculation starts with the round-trip distance for one commuting day. Suppose the commute is 15 miles each way. Daily commute distance is 30 miles. Five days a week is 150 miles per week. At 30 MPG, 150 divided by 30 equals 5 gallons per week. At $3.50 per gallon, 5 times $3.50 equals $17.50 per week. If the user enters 50 commuting weeks, $17.50 times 50 equals $875 per year. The page can divide the annual amount by 12 to show an average monthly fuel cost.
Visual: Commute Cost Timeline
Daily cost scales up to a weekly cost, an average monthly cost, and an annual cost based on your commute days per week and weeks per year.
How a commute cost scales from daily to annual
Period
Basis
Daily
One round-trip commuting day
Weekly
Daily cost times commute days per week
Average Monthly
Annual cost divided by 12
Annual
Weekly cost times commute weeks per year
Why Monthly Fuel Cost Is an Estimate
Calendar months do not contain the same number of workdays. Vacations, holidays, remote-work days, and schedule changes also affect commuting. That is why the calculator bases the annual estimate on days per week and weeks per year, then labels the results Annual Estimate and Average Monthly Estimate.
How Much Does Better MPG Save?
Suppose two vehicles both travel 12,000 miles per year. Vehicle A gets 20 MPG and Vehicle B gets 30 MPG. Vehicle A uses 12,000 divided by 20, which equals 600 gallons. Vehicle B uses 12,000 divided by 30, which equals 400 gallons. The difference is 200 gallons per year. At $3.50 per gallon, 200 times $3.50 equals $700. The actual savings depend on annual miles, fuel price, and real-world MPG.
Visual: Vehicle A vs. Vehicle B Fuel Needed
Default example: 12,000 miles per year at 20 MPG versus 30 MPG. Calculate your own comparison above to update this chart. Figures are presented neutrally and do not recommend which vehicle to buy.
Fuel needed for Vehicle A compared with Vehicle B
Vehicle
Fuel Needed
Vehicle A (20 MPG)
600.00 gal
Vehicle B (30 MPG)
400.00 gal
Should I Use City, Highway, or Combined MPG?
Use the rating that best matches the planned driving. City MPG generally reflects lower-speed stop-and-go driving. Highway MPG reflects highway-oriented testing. Combined MPG blends the two for a general comparison. A road trip that is mostly highway may differ from daily mixed driving. If you know your own measured MPG, that can be especially useful because it reflects your vehicle and driving habits.
Does the Calculator Use Live Gas Prices?
It should not, and it does not, silently assume a live price. Fuel prices vary by location, fuel grade, station, date, and fuel type. Enter the price you actually expect to pay. If a future integration is added for live prices, it should clearly display the data source and timestamp. This calculator does not hardcode a national average that becomes stale.
Fuel Cost vs Total Driving Cost
Fuel is only one part of the cost of operating a vehicle. Other costs can include maintenance, tires, repairs, insurance, registration, depreciation, tolls, and parking. This page focuses on fuel. That keeps the calculation transparent: distance, fuel economy, and fuel price.
Fuel Cost Calculator vs Gas Mileage Calculator
Use the Fuel Cost Calculator when you already know or estimate MPG and want to calculate money. Use the Gas Mileage Calculator when you know miles driven and gallons used and want to calculate actual MPG. The tools complement each other. You can measure real MPG first, then use that result to estimate future fuel costs.
The Bottom Line
Fuel cost is determined by how far you drive, how efficiently the vehicle uses fuel, and what the fuel costs. For US MPG, that is distance divided by MPG, multiplied by fuel price. For metric L/100 km, that is distance multiplied by L/100 km, divided by 100, multiplied by price per liter. CalculateThisWay shows both the cost and the underlying fuel quantity so you can understand exactly how the estimate was produced.
Worked Fuel Cost Examples
The examples below use the exact same calculation engine as the calculator above. Values are computed live in JavaScript rather than typed in as fixed text, so they will always match what the calculator itself would return for these inputs.
300-Mile Trip at 30 MPG
Distance 300 mi one way. 30 MPG. $3.50 per gallon.
500-Mile Trip at 25 MPG
Distance 500 mi one way. 25 MPG. $3.40 per gallon.
150-Mile Round Trip at 30 MPG
Distance 150 mi one way, round trip. 30 MPG. $3.50 per gallon.
500 km at 8 L/100 km
Distance 500 km one way. 8 L/100 km. 1.70 per liter.
15-Mile Commute, 5 Days a Week
One-way commute 15 mi. 30 MPG. $3.50 per gallon. 5 days per week.
Compare: 20 MPG vs 30 MPG
12,000 miles per year. $3.50 per gallon.
Try It Yourself
A 500-mile one-way trip, 25 MPG, $3.40 per gallon, split between 2 people.
What is the total fuel cost, and what does each person pay?
Fuel needed: 500 divided by 25 equals 20 gallons. Fuel cost: 20 times $3.40 equals $68. Per person: $68 divided by 2 equals $34 each.
Which Calculator Do I Need?
Fuel Cost Calculator (this page)
I know or can estimate my MPG and want to calculate money and fuel needed for a trip or commute.
Divide your trip distance by your vehicle's fuel economy to get the fuel needed, then multiply that amount by the price per gallon or liter. The Trip Fuel Cost calculator above does this automatically and shows every step.
How much gas will my trip cost?
Enter your distance, your vehicle's MPG or L/100 km, and the fuel price you expect to pay into the calculator above. It returns the fuel needed and the total estimated cost, plus cost per mile or kilometer.
How much gas do I need for 100 miles?
Divide 100 by your vehicle's MPG. At 25 MPG that is 100 divided by 25, which equals 4 gallons. A different MPG will change the answer, so enter your own vehicle's fuel economy for an accurate figure.
How much gas do I need for 300 miles?
Divide 300 by your vehicle's MPG. At 30 MPG that is 300 divided by 30, which equals 10 gallons. At $3.50 per gallon, that is an estimated fuel cost of $35.
How much gas for 500 miles?
It depends on fuel economy. At 20 MPG that is 25 gallons, at 25 MPG that is 20 gallons, and at 40 MPG that is 12.5 gallons. Enter your own expected MPG above for the closest estimate.
How much gas for 1,000 miles?
Divide 1,000 by your vehicle's MPG to get gallons needed, then multiply by your fuel price. The calculator above performs this calculation instantly for any distance you enter.
How much does a 500-mile road trip cost?
At 25 MPG and $3.40 per gallon, a 500-mile trip needs 500 divided by 25, which equals 20 gallons, and 20 times $3.40 equals $68. Change the MPG or price above to match your own vehicle and local pump price.
How do I calculate a round-trip gas cost?
Double the one-way distance before dividing by MPG. A 150-mile one-way destination becomes a 300-mile effective round-trip distance, which the calculator displays explicitly so you can see whether the mileage was doubled.
What MPG should I use?
Use the rating that best matches your planned driving. Combined MPG is a reasonable general planning number, city MPG fits stop-and-go driving, and highway MPG fits long highway trips. Your own measured average MPG can be even more useful.
Where can I find my car's MPG?
The official U.S. FuelEconomy.gov resource, maintained by the EPA and the Department of Energy, provides city, highway, and combined MPG ratings by vehicle year, make, and model.
Why is my real MPG lower than EPA MPG?
EPA explains that actual fuel economy varies with factors such as speed, acceleration, weather, air conditioning, road conditions, traffic, vehicle load, maintenance, tires, and terrain, so your real-world result commonly differs from the label.
How do I calculate gas cost per mile?
Divide total fuel cost by total distance. For a 300-mile trip costing $35, that is $35 divided by 300, which equals about $0.1167 per mile, or roughly 11.7 cents of fuel per mile.
What is gallons per 100 miles?
Gallons per 100 miles is 100 divided by MPG. It is the consumption figure shown on EPA fuel economy labels because fuel consumed relates directly to fuel cost, and it helps explain why MPG improvements are nonlinear.
Why is MPG nonlinear?
Because MPG is a rate, not a straight-line measurement. Going from 15 to 20 MPG saves far more fuel over a fixed distance than going from 35 to 40 MPG, even though both are a 5 MPG increase. This is sometimes called the MPG illusion.
How do I calculate fuel cost in L/100 km?
Multiply distance in kilometers by L/100 km, then divide by 100 to get liters needed. Multiply liters by the price per liter for total cost. At 500 km and 8 L/100 km, that is 500 times 8 divided by 100, which equals 40 liters.
How do I calculate km/L?
Divide distance in kilometers by km/L to get liters used. Higher km/L means better fuel economy, similar to MPG, while L/100 km works the opposite way, so do not interchange the two numbers directly.
How do I split gas money?
Divide the total fuel cost by the number of people sharing the trip for an equal fuel-cost split. The calculator shows this automatically when you enter more than one person sharing the cost.
How much should each passenger pay for gas?
For an equal split, each passenger pays total fuel cost divided by the number of people. Whether the driver should also pay a share, or whether other costs should be included, is left to the people traveling.
How do I calculate commute fuel cost?
Double your one-way commute distance for a daily round trip, multiply by days commuted per week for a weekly distance, and multiply by weeks commuted per year for an annual distance. The Commute Fuel Cost mode above does this and converts each period to fuel and cost.
How much gas do I use driving to work?
It depends on your one-way distance and your vehicle's fuel economy. Enter both into the Commute Fuel Cost mode above to see daily, weekly, average monthly, and annual fuel use.
How do I estimate monthly gas cost?
Because calendar months have different numbers of workdays, the calculator estimates an annual cost from your days per week and weeks per year, then divides by 12 for an average monthly figure rather than treating every month as identical.
How do I estimate annual fuel cost?
Multiply your weekly fuel cost by the number of weeks you commute or drive per year, or divide your annual distance by MPG and multiply by fuel price. The Commute Fuel Cost mode shows this calculation in full.
How much can better MPG save?
For 12,000 miles per year at $3.50 per gallon, 20 MPG uses 600 gallons and 30 MPG uses 400 gallons, a 200 gallon difference worth about $700 per year. Use Compare Two Vehicles above with your own numbers for a personalized estimate.
Does the calculator use current gas prices?
No. Fuel prices vary by location, station, fuel grade, and date, so this calculator never assumes a live or national average price. Enter the pump price you actually expect to pay.
Are tolls included?
No. This calculator estimates fuel cost only. Tolls, parking, and other trip expenses are not included and would need to be added separately.
Is maintenance included?
No. Maintenance, tires, repairs, and similar costs are not part of this fuel-only estimate. This calculator focuses on distance, fuel economy, and fuel price.
Is this total vehicle ownership cost?
No. Fuel is only one part of operating a vehicle. Insurance, maintenance, tires, repairs, registration, depreciation, tolls, and parking are not included in this fuel cost estimate.
What is the difference between Fuel Cost and Gas Mileage calculators?
Use the Fuel Cost Calculator when you already know or estimate your MPG and want to calculate money and fuel needed. Use the Gas Mileage Calculator when you know miles driven and gallons used and want to calculate your vehicle's actual MPG.
U.S. EPA / U.S. Department of Energy: FuelEconomy.gov, the official federal fuel economy resource - fueleconomy.gov
Methodology & Limitations
Fuel needed is calculated as effective distance divided by MPG for US mode, or effective distance times L/100 km divided by 100 (or effective distance divided by km/L) for metric mode, where effective distance already accounts for round trip and number of trips.
Fuel price, tank capacity, and currency symbol are always user-entered. This calculator never hardcodes a current or national average gas price, and it performs no currency conversion.
This calculator estimates fuel cost only and does not include insurance, maintenance, tires, repairs, registration, depreciation, tolls, or parking.
Commute annual and average-monthly figures are estimates based on the days per week and weeks per year you enter, not a guarantee of actual workdays.
Compare Two Vehicles presents fuel needed, cost, and differences neutrally. It does not recommend which vehicle to buy.
This calculator estimates fuel cost from known or estimated fuel economy. It is not the Gas Mileage Calculator, which instead calculates actual MPG from miles driven and fuel added.
This calculator provides a fuel-only cost estimate based on the distance, fuel economy, and fuel price you enter. It does not include insurance, maintenance, tires, repairs, registration, depreciation, tolls, or parking, and it is not a substitute for your vehicle's actual fuel economy, which EPA notes can vary with driving conditions. Fuel prices change constantly and vary by location, so always enter the price you actually expect to pay rather than relying on a built-in figure.