Planning a road trip, or wondering what a drive really costs? Enter the trip distance, your car’s fuel economy and the price at the pump, and the calculator shows the total gas cost, how many gallons (or liters) you’ll burn and the cost per mile. Don’t know your MPG? Tap a car type for a typical figure. Switch to Round trip to double the distance, and pick how many people are splitting the cost to see what each person pays. Use the toggle for UK units (miles, MPG and price per litre — you can type the pump price in pence, like 145.9) or metric units (km and L/100 km).
How it works: fuel needed = distance ÷ MPG (or distance × L/100 km ÷ 100), and cost = fuel needed × price per gallon or liter; round trip doubles the distance. UK MPG uses the imperial gallon (4.546 L), which is about 20% bigger than the US gallon (3.785 L), so the same car shows a higher MPG in the UK. If your car reports km per liter, 100 ÷ km/L gives L/100 km. Car-type presets are rough typical figures — your own car’s highway MPG is better for long drives, and the “10% extra” row is a safer number to budget with.