Free Rental Car Fuel Cost calculator with clear step-by-step results.
Fuel is usually the largest variable cost of a rental after the rate itself, and rental companies price it at a premium. Distance and consumption give the litres burned; the pump price gives what a self-service refill costs. The desk figure applies the fuel-purchase-option or refuelling-service markup, which is typically 20-40% above street price, so the gap between the two numbers is what returning the car full actually saves.
Fuel used
Litres = distance ÷ 100 × consumption (L/100km)
Cost comparison
Pump cost = litres × price; desk cost = pump cost × (1 + markup)
Fuel prices move daily and rental refuelling charges vary by supplier and location. Check the rental agreement for the exact refuelling policy and per-litre rate.
Only if you will return the tank nearly empty and value the time saved, since unused fuel is not refunded. Returning full at a station near the airport is almost always cheaper.
Add roughly 10-20% to the manufacturer's combined figure for real-world driving, and more for mountains, heavy loads or constant air conditioning. A small hatchback typically runs 6-8 L/100km, a mid-size SUV 9-12.
For US mpg, L/100km = 235.2 ÷ mpg. For imperial mpg, use 282.5 ÷ mpg.