Units-Calc

Trip Cost Calculator

Calculate the full cost of any journey — fuel, extras like tolls and parking, return trips, and cost per person. Compare petrol vs diesel vs EV side by side.

Calculate trip cost

Journey

Vehicle & Fuel

Extra costs (optional)

Tips to reduce trip costs

Check tyre pressure

Under-inflated tyres increase rolling resistance and can reduce fuel economy by up to 3%. A quick check before a long trip costs nothing.

Reduce speed on motorways

Driving at 60 mph instead of 70 mph can improve fuel economy by around 10–15%, which adds up significantly on longer journeys.

Share the ride

Adding even one extra passenger halves the fuel cost per person. Use the travellers field above to see how much you each save.

Fill up away from motorways

Motorway service stations typically charge 10–15p per litre more than supermarket forecourts. Plan fuel stops in advance to save.

How the calculation works

The calculator converts your distance and fuel economy into litres (or kWh for EVs) consumed, multiplies by the unit price, adds any extra costs, and optionally doubles the distance for a return journey. The total is then divided by the number of travellers for a per-person share.

Petrol / Diesel (MPG)

Distance → miles ÷ mpg = UK gallons × 4.546 = litres × price/litre

Petrol / Diesel (L/100km)

Distance → km ÷ 100 × L/100km = litres × price/litre

Electric (EV)

Distance → miles ÷ miles/kWh = kWh × electricity rate (£/kWh)

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