Calculate fuel cost for a journey

Estimate the litres and pump cost for a journey from L/100 km or UK Imperial mpg.

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ToolFuel Cost Calculator
Input
Output
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Preview

How it works

In metric mode, kilometres ÷ 100 × L/100 km gives litres used. In mpg mode, miles ÷ Imperial mpg gives gallons, each converted using NIST’s 4.54609 litres per UK gallon, before litres are multiplied by the entered fuel price.

Formula
metric litres = kilometres ÷ 100 × litres per 100 km
  • L/100 km is the initial format, but trip distance, measured consumption, and local per-litre price are required.
  • No live pump price or route-specific efficiency is supplied.

Worked example

A 300km trip
8 litres per 100km at 1.60 a litre
Input
											Distance: 300
Consumption: 8
Fuel price per litre: 1.6
Output
												Litres used: 24
Total cost: 38.4
Cost per distance unit: 0.13
Distance unit: km

When to use this

Road-trip planning estimates pump spend, vehicle comparisons apply one journey to two consumption figures, and passengers can divide the resulting fuel-only total separately.

Edge cases

  • US mpg is based on a 3.785412-litre gallon and will be understated if entered in the UK Imperial mpg mode, which uses 4.54609 litres.
  • A mixed-driving dashboard average may not match motorway, towing, winter, or heavily loaded consumption; the entered figure is applied unchanged.
  • Tolls, parking, charging, maintenance, depreciation, and an omitted return leg do not enter the fuel-only total.

References