Before setting off on a holiday road trip, heading to a client meeting or analysing your monthly commuting costs – the fuel cost calculator shows you exactly how much petrol or diesel a given journey will cost. It is invaluable for expense reports, comparing road travel against train or air, and deciding whether a more economical vehicle would pay off.
Step by Step: How to Use the Fuel Cost Calculator
- Enter the distance: Input the planned journey distance in kilometres – for example 430 km one way or 860 km for a return trip.
- Enter fuel consumption: Find your vehicle's official consumption figure in the vehicle registration document or manufacturer documentation – in litres per 100 km.
- Enter the fuel price: Enter the current price per litre at the pump – or an average price for longer-term planning.
- Calculate cost per person: If travelling with passengers, enter the number of people to split the costs fairly.
- Read the result: The calculator displays total cost, litres consumed, cost per kilometre and, if needed, cost per person.
Practical Examples
Example 1 – Weekend trip Hamburg to Munich: 780 km, VW Golf with 6.2 L/100 km, petrol £1.72/L. Consumption: 780 / 100 × 6.2 = 48.36 L. Cost: 48.36 × 1.72 = £83.18. Split four ways: £20.80 per person – cheaper than a train ticket.
Example 2 – Daily commute: 38 km each way, 76 km per day. Over 220 working days: 76 × 220 = 16,720 km/year. SUV with 9.5 L/100 km, diesel at £1.65/L: 16,720 / 100 × 9.5 × 1.65 = £2,620.68/year in fuel alone.
Example 3 – Measure your actual consumption: Start with a full tank, drive 432 km, refuel with 35.1 L. Actual consumption: 35.1 / 432 × 100 = 8.13 L/100 km – well above the official figure of 6.5 L because much of the driving was in town.
Fuel Cost Formula: Consumption and Costs
Formula: Cost = (Distance km / 100) × Consumption (L/100 km) × Price (£/L). Example: 500 km, 7 L/100 km, £1.65/L = £57.75. To measure consumption: litres filled / kilometres driven × 100.
Frequently Asked Questions (FAQ)
Why is my actual fuel consumption higher than the official figure?
Official consumption figures are measured under controlled laboratory conditions (WLTP cycle). In everyday use, short trips (cold engine), air conditioning, motorway speeds above 130 km/h, load and driving style typically increase consumption by 20–40%. Use your measured real-world consumption for realistic planning.
How do I calculate cost per kilometre?
Cost per km = (Consumption L/100 × Price £/L) / 100. At 7 L/100 km and £1.72/L: (7 × 1.72) / 100 = £0.1204/km = 12.04 pence/km. For business mileage claims, check the current HMRC approved mileage rates.
Is it worth making a detour to find cheaper fuel?
Example: 10p/L saving, 50 L tank = £5 saved. An 8 km detour at 7 L/100 km costs: 0.56 L × £1.75 = about £0.98 extra. The saving clearly outweighs the cost – but with only 20 litres and a 2p difference, it barely makes sense.
