Quickly estimate how much your journey will cost. Choose miles or kilometres, pick your vehicle’s efficiency (US MPG, UK MPG, L/100km or km/L), enter the fuel price per litre or per gallon and select your currency. See litres needed, total trip cost, cost per mile/km and cost per person.
What the calculator shows
Keep tyres at the recommended pressure and remove roof racks when not needed.
Example (for clarity)
Distance: 120 miles (one-way), Round trip: on → 240 miles.
Efficiency: 30 US MPG. Price: $3.90 per US gallon.
Fuel needed ≈ (240 ÷ 30) × 1 US gal = 8.0 gal ≈ 30.28 L.
Trip cost ≈ 8.0 × $3.90 = $31.20.
Cost per mile ≈ $31.20 ÷ 240 = $0.13/mi (≈ $0.08/km).
Q1) What’s the difference between US MPG and UK MPG?
A) A UK gallon is larger (4.546 L) than a US gallon (3.785 L). The same car will show a higher MPG value in UK terms.
Q2) L/100km vs km/L — which should I use?
A) L/100km is “litres used per 100 km” (lower is better). km/L is “kilometres per litre” (higher is better). Use the format your vehicle or market publishes.
Q3) Can I enter the fuel price per gallon?
A) Yes. Choose per US gallon or per UK gallon in the “Price unit” menu and the calculator converts it to price per litre internally.
Q4) Does the calculator update live fuel prices automatically?
A) No. Enter the current pump price from your local station or a price app for the most accurate result.
Q5) Is the result exact?
A) It’s an estimate. Real costs vary with speed, traffic, temperature, load, terrain and driving style.
Q6) Petrol vs diesel — do I need to set anything?
A) No special toggle. Just enter your vehicle’s real-world efficiency and the actual price for your fuel type.
Q7) How do round trips work?
A) When “Round trip” is on, distance is doubled automatically and the outputs update accordingly.
Q8) Can I split the cost between passengers?
A) Yes. Set the number of people and the calculator shows a per-person share.
Q9) Why is my cost per mile different from the sticker figures?
A) Official MPG ratings are laboratory estimates. Your real-world efficiency depends on driving conditions and maintenance.
Q10) Does currency affect the calculation?
A) Only the display. Currency changes how results are shown, not the underlying litres and distance maths.
Q11) Can I save or share my inputs?
A) Use the Share button to copy a link with your inputs pre-filled. The calculator also remembers your last session in your browser.
Q12) Are my details stored on a server?
A) No. Inputs are processed in your browser, and saved locally only if your browser allows.