Fuel costs: what a trip will cost at the pump
The cost of a road trip is often a surprise: fuel prices vary by country and region, consumption depends on the vehicle and driving style, and the route distance is rarely a straight line. A fuel cost calculator turns distance, consumption, and fuel price into an exact budget for the journey, helping drivers compare routes, vehicles, and petrol versus diesel choices before leaving the driveway.
TL;DR
- The fuel consumed is the distance divided by the vehicle efficiency (liters per 100 km or miles per gallon), multiplied by 100 or converted accordingly
- Formula: Fuel (L) = Distance (km) ÷ 100 × Consumption (L/100km) | Cost = Fuel × Price p
- Example 1: A 600 km trip at 6.5 L/100km with diesel at €1.70/L
How it works
The fuel consumed is the distance divided by the vehicle efficiency (liters per 100 km or miles per gallon), multiplied by 100 or converted accordingly. The cost is the fuel consumed times the price per liter or gallon. The calculator accepts either metric or imperial units and converts between them automatically.
The math
Divide the route distance by 100, multiply by the consumption in liters per 100 km to obtain the liters needed, then multiply by the price per liter. For imperial units, divide the distance in miles by the mpg rating to obtain gallons, then multiply by the price per gallon. The result is the single-trip fuel budget.
In imperial units the same logic becomes: Gallons = Miles ÷ MPG, then Cost = Gallons × Price per Gallon.
Examples
Example 1: A 600 km trip at 6.5 L/100km with diesel at €1.70/L
- Fuel used: 600 ÷ 100 × 6.5 = 39 L
- Cost: 39 × €1.70 = €66.30
- Per person (2 travelers): €33.15
- Total round trip: €132.60
Example 2: Comparing a 5 L/100km hybrid vs a 9 L/100km SUV
- Hybrid over 15,000 km: 750 L → €1,275 at €1.70/L
- SUV over 15,000 km: 1,350 L → €2,295
- Annual difference: €1,020
- The efficiency gap is worth a comparison before buying
When to use it
✦ Trip Budgeting
Families and travelers estimate the fuel budget for holidays, comparing routes and stopovers before departure.
✦ Vehicle Purchase Decisions
Buyers compare the annual fuel costs of different cars, adding the real operating cost to the purchase price when choosing a vehicle.
⚠ Common mistakes
- Mixing Metric and Imperial Units: Using mpg with liter prices produces wildly wrong results; convert consistently.
- Using Highway Consumption for City Trips: City consumption can be 30-50% higher than the highway figure, understating real costs.
- Forgetting Price Differences: Fuel prices vary by up to 30% between countries and regions; the same trip costs very differently across borders.
FAQ (6)
How do I find my car consumption?
Check the owner manual or on-board computer; the real-world figure is usually higher than the official WLTP test value.
Does driving style affect consumption?
Yes, smooth acceleration, steady speeds near 90-110 km/h, and proper tire pressure can save 10-20% of fuel.
If I type my salary or prices here, do you store them?
No — and that's deliberate. Everything runs locally in your browser, nothing leaves your device. We don't see your net salary, your margins, or the VAT numbers you test. For a finance tool that matters: you can run a quick check on a payslip or an invoice while on public Wi-Fi and close the tab knowing no trace is kept server-side.
Can I use it on the train without signal to check an invoice?
Yes. Load the page once, then it works offline. VAT, discount and mortgage math are all pure JavaScript — no API call. I often test it in airplane mode: open the mortgage page, type 250,000 at 4.5% for 25 years, you get the schedule instantly, even in a tunnel.
Can I file taxes with these results?
Use it as a fast sanity check, not as the final filing. Formulas are standard (e.g. Net = Gross / 1+VAT) and verified against official sources listed at the bottom, but rates and thresholds change — Italy's 22% vs Germany's 19%, or IRPEF brackets. For the actual declaration, double-check with your accountant or Agenzia delle Entrate / HMRC / IRS.
How do I send a calculation to my accountant?
Hit 'Share Link' under the results. It encodes the inputs in the URL — e.g. ?price=1200&vat=22 — so your accountant opens the exact same view, no screenshot needed. You can also copy the result with one tap and paste it into an email.