# Free online fuel cost calculator > Fuel cost is distance divided by efficiency, multiplied by the price per unit. This calculator handles both MPG (US) and L/100km (metric) so you can price any road trip or daily. Calculate the total fuel cost for any trip. Enter distance, fuel efficiency, and price per gallon or liter to see total cost, fuel used, and cost per mile or kilometer in both MPG and L/100km modes. **Interactive version:** https://onlinecalculator.me/everyday/fuel-cost/ **Category:** Everyday ## How to use 1. Toggle MPG or L/100km to match how your car's efficiency is rated. 2. Enter the trip distance in miles or kilometers. 3. Enter your car's fuel efficiency (MPG or L/100km). 4. Enter the current gas or diesel price per gallon or liter. 5. Read total cost, fuel used, and cost per mile or per kilometer. ## Formulas **MPG mode:** ``` fuel used (gal) = distance (mi) ÷ MPG total cost = fuel used × price per gallon cost per mile = price per gallon ÷ MPG ``` **L/100km mode:** ``` fuel used (L) = (distance (km) ÷ 100) × L/100km total cost = fuel used × price per liter cost per km = (L/100km ÷ 100) × price per liter ``` ## Worked examples **US road trip:** 300 miles at 30 MPG, gas at $3.50/gallon: ``` fuel used = 300 ÷ 30 = 10 gallons total cost = 10 × 3.50 = $35.00 cost/mile = 3.50 ÷ 30 = $0.12 ``` **European drive:** 500 km at 7 L/100km, fuel at €1.75/liter: ``` fuel used = (500 ÷ 100) × 7 = 35 liters total cost = 35 × 1.75 = €61.25 cost/km = (7 ÷ 100) × 1.75 = €0.1225 ``` ## Notes - Actual fuel economy is usually 10–20% lower than EPA/WLTP ratings in real-world driving. - Highway driving is more efficient than city driving for most non-hybrid vehicles. - For electric vehicles, substitute kWh/100mi or mi/kWh and price per kWh for a comparable cost estimate. ## Frequently asked questions ### How do I calculate fuel cost for a road trip? Fuel cost = (distance ÷ MPG) × price per gallon. For example, a 300-mile trip at 30 MPG with gas at $3.50/gal costs (300 ÷ 30) × 3.50 = $35.00. The calculator shows this instantly. ### How do I convert MPG to L/100km? L/100km = 235.21 ÷ MPG. So 30 MPG is about 7.84 L/100km. Switch the unit toggle at the top and enter your metric values directly — no manual conversion needed. ### What is a good MPG for a car? For a non-electric passenger car: under 25 MPG is below average, 25–35 MPG is average, 35–50 MPG is efficient (hybrids), and 50+ MPG is hybrid or plug-in hybrid territory. EPA fuel economy labels list combined city/highway MPG. ### How does the L/100km mode work? In L/100km mode, fuel used = (distance in km ÷ 100) × L/100km value. A 500 km trip at 9 L/100km uses 45 liters. Cost = 45 × price per liter. ### What is cost per mile and why is it useful? Cost per mile = price per gallon ÷ MPG. It lets you compare vehicles with different fuel efficiencies on an equal footing. At $3.50/gal and 30 MPG, you pay about $0.12 per mile. ## Sources - [Fuel Economy](https://www.epa.gov/fueleconomy) — U.S. Environmental Protection Agency - [Gasoline Vehicles: Learn More About the Label (MPG)](https://www.fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml) — FuelEconomy.gov (U.S. DOE/EPA) ## Related calculators - [Tip calculator](https://onlinecalculator.me/everyday/tip/) — Calculate a tip and split the bill among any number of people. - [Discount calculator](https://onlinecalculator.me/everyday/discount/) — Find the final price after any percentage discount or sale. - [Auto loan calculator](https://onlinecalculator.me/finance/auto-loan/) — Calculate monthly payments, total interest, and payoff schedule for a car loan. - [Percentage calculator](https://onlinecalculator.me/math/percentage/) — Work out percentages for price changes, fuel cost splits, and more. - [Length converter](https://onlinecalculator.me/unit-converters/length/) — Convert between miles, kilometers, feet, and meters for distance planning. --- Part of [onlinecalculator.me](https://onlinecalculator.me/) — free calculators that run entirely in your browser. Machine-readable index: https://onlinecalculator.me/llms.txt