Fuel Cost Calculator – Trip Gas Cost
Estimate fuel needed and driving cost for a trip or regular commute. Enter the distance, fuel economy, and fuel price; choose Trip or Commute for the relevant results.
Estimate Trip and Commute Fuel Expenses
Fuel Cost Formula
Where:
- \(F_{\mathrm{L}}\) — fuel needed, in liters
- \(D_{\mathrm{km}}\) — total distance driven, in kilometers
- \(r\) — fuel consumption, in liters per kilometer
- \(p_{\mathrm{L}}\) — fuel price per liter, in your chosen currency
- \(C\) — total fuel cost, in the same currency
The calculator converts the selected distance, fuel economy, and price units before applying the formula. For a round trip, it doubles the entered one-way distance; for a commute, it doubles the one-way distance and multiplies by commute days per week.
Fuel Cost – Calculation Example
Example: Use the default Trip settings: 120 miles one way, Round trip, 30 MPG (US), fuel priced at 4 per US gallon, and one person paying.
\[D=120\times2=240\text{ miles}\]
\[F=\frac{240}{30}=8\text{ US gal}\]
\[C=8\times4=32\]
Result: the trip needs 8 US gallons (about 30.283 liters) and costs 32 currency units in total. With one person paying, the cost per person is 32; the fuel cost per mile is approximately 0.1333 currency units.
How to use the calculator
- Set Tab to Trip for a single journey or Commute for a recurring weekly journey.
- For Trip, enter Trip distance and select its Distance unit. Enter the one-way distance even if you plan to return, then choose One way or Round trip under Trip type.
- For Commute, enter One-way commute distance, select its Distance unit, and enter Commute days per week. The calculator assumes you travel to and from your destination on each of those days.
- Enter your vehicle’s Fuel economy and choose the matching Fuel economy unit: MPG (US), MPG (UK), L/100 km, or km/L. Use a figure representative of the driving you expect.
- Enter Fuel price and choose whether the Price unit is per US gallon or per liter. Enter a number without a currency symbol.
- For Trip, set People splitting trip cost if the fuel expense will be shared equally. Read the fuel-needed and cost results for your selected tab.
What the fuel cost estimate means
Fuel cost depends on how far you drive, how much fuel the vehicle uses over that distance, and the price of that fuel. The calculator reports fuel needed in both liters and US gallons, regardless of which units you entered. It then uses your selected price unit to calculate cost. A fuel price of 4 per US gallon is not treated as 4 per liter.
In Trip mode, Total trip cost covers the entire selected journey: one way or round trip. Cost per person divides that fuel cost equally by the number of people entered. Trip cost per mile and Trip cost per kilometer divide the total fuel cost by the total distance driven, not just the one-way distance. These figures can help compare routes of different lengths, although they do not include tolls, parking, or vehicle wear.
In Commute mode, fuel needed and Weekly commute cost cover all entered commute days in one week. Average monthly commute cost is the weekly cost multiplied by 52 and divided by 12; Yearly commute cost is the weekly cost multiplied by 52. These are annualized estimates, not predictions for a particular calendar month. For example, a 15-mile one-way commute on five days a week totals 150 miles weekly. At 30 MPG (US) and 4 per US gallon, that is 5 US gallons and 20 currency units per week, or about 86.67 per average month.
Assumptions and practical tips
Match the fuel economy unit to your source. MPG (US) and MPG (UK) use different gallon sizes and produce different fuel estimates for the same number. L/100 km measures fuel consumed per distance, so a lower value means better economy; with MPG or km/L, a higher value means better economy. If you have recent fill-up and distance records, the Gas Mileage Calculator can help you estimate a more representative figure.
The estimate assumes constant fuel economy and fuel price throughout the journey. Traffic, hills, speed, weather, vehicle load, and idling can change actual consumption. For a long drive, consider planning refueling with the Road Trip Fuel Stops Calculator. To account for expenses beyond fuel, use the Travel Budget Calculator.
Commute calculations assume the same round-trip distance on every entered day for 52 weeks. Adjust the number of days or use a shorter planning period if you expect holidays, remote-work days, or a changing schedule. Cost splitting applies only in Trip mode and does not change the amount of fuel the vehicle needs.
Frequently Asked Questions
How can I calculate trip fuel cost by hand?
Use the units printed with your fuel economy and price. If both use US gallons, divide total miles driven by US MPG to get gallons, then multiply by the price per US gallon. If your economy is in L/100 km, multiply total kilometers by that figure and divide by 100 to get liters; then multiply by the price per liter. Include every leg of the journey.
What is a good fuel economy for a car?
A good value depends on the vehicle and driving conditions. Around 30 US MPG is a reasonable comparison point for many gasoline passenger cars; 40 US MPG or more is relatively efficient. Larger vehicles, city traffic, and cold weather can produce lower figures, while hybrids may do substantially better. For a useful cost estimate, prioritize your own recent driving records over a published rating.
How do I convert L/100 km to MPG?
Divide 235.215 by the L/100 km value to get US MPG, or divide 282.481 by it to get UK MPG. For example, 6 L/100 km is about 39.2 US MPG or 47.1 UK MPG. These are different because a UK gallon is larger than a US gallon. Check which version of MPG your vehicle’s display or source uses.
Can I enter a fuel price quoted per UK gallon?
Not directly: the available gallon-price option means per US gallon. Divide the UK-gallon price by 4.54609 to get a price per liter, then select “per liter.” Alternatively, multiply the UK-gallon price by about 0.83267 to get a price per US gallon. Keep the same currency throughout; converting gallons does not convert pounds to dollars or any other currency.
What if my return route is longer than my outbound route?
Add the actual distances for both legs and enter the sum as a one-way trip, rather than selecting Round trip. The round-trip setting assumes the return covers the same distance as the outbound journey. If the legs also have very different fuel economy—for example, because one involves a mountain climb—estimate each leg separately and add their fuel costs.
How should I estimate a trip with different fuel prices along the way?
Calculate the fuel used in each portion of the trip and multiply it by the relevant price, then add the costs. For a quick estimate, you can instead enter an expected average price, weighted toward where you expect to buy more fuel. Actual spending at the pump may differ from fuel consumed on this trip if you start or finish with fuel already in the tank.
Does this calculator work for diesel, hybrid, or electric vehicles?
It works for diesel and fuel-burning hybrids if you enter an appropriate fuel economy figure and the matching fuel price. A hybrid’s electric assistance is already reflected in a representative measured MPG or L/100 km figure. It does not directly calculate charging costs for a fully electric vehicle: those require electricity use, typically in kWh per distance, and a price per kWh.