Fuel Cost Calculator — Trip Gas Cost & Consumption
This free fuel cost calculator estimates how much you'll spend on fuel for any trip — whether a daily commute, a cross-country road trip, or a business journey. Enter the distance, the price of fuel at the pump, and your vehicle's fuel consumption rating to get instant, accurate results.
The calculator supports both Metric (km and litres per 100 km, L/100 km) and Imperial (miles and miles per gallon, MPG) unit systems, and includes 8 popular currency symbols for the fuel price input.
How Fuel Cost Is Calculated
Total cost = Fuel needed × Price per litre
Cost per km = Total cost ÷ Distance
Total cost = Fuel needed × Price per gallon
Cost per mile = Total cost ÷ Distance
MPG vs L/100 km — Which Should You Use?
MPG (miles per gallon) and L/100 km (litres per 100 kilometres) measure the same thing — fuel efficiency — but they work inversely. A higher MPG means better efficiency. A lower L/100 km means better efficiency.
| L/100 km | MPG (UK) | MPG (US) | Efficiency |
|---|---|---|---|
| 4.0 | 70.6 | 58.8 | Excellent (hybrid/EV range extender) |
| 5.0 | 56.5 | 47.1 | Very good (compact/hybrid) |
| 6.0 | 47.1 | 39.2 | Good (modern compact) |
| 7.0 | 40.4 | 33.6 | Average (mid-size sedan) |
| 8.0 | 35.3 | 29.4 | Below average (larger car) |
| 10.0 | 28.2 | 23.5 | Poor (SUV / older vehicle) |
| 12.0 | 23.5 | 19.6 | Very poor (truck / large SUV) |
To convert: MPG (US) = 235.21 ÷ L/100 km
CO₂ Estimate
The calculator also shows an approximate CO₂ emission for your trip based on standard emission factors:
The calculator uses the petrol/gasoline factor as the default — a widely applicable average. Actual emissions vary by fuel type, vehicle age, and engine condition.
Frequently Asked Questions
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