Convert fuel economy between L/100 km, km/L and mpg
Estimate fuel cost for a trip
Enter the distance and price per litre to see how much fuel the trip requires and what it costs. The tool converts consumption to L/100 km and uses litres = L/100 km × kilometres / 100, then multiplies litres by the pump price. This covers fuel only, not parking, tolls, wear, or depreciation.
Fuel economy figures can look completely different even when they describe the same car. Europe commonly uses litres per 100 kilometres, some countries use kilometres per litre, and the US and UK often use miles per gallon.
Consumption versus distance per unit
L/100 km measures fuel consumed over a fixed distance, so lower is better. Km/L and mpg measure distance travelled with a fixed amount of fuel, so higher is better. Because the direction changes, you cannot compare the raw numbers.
For example, 5 L/100 km equals 20 km/L. Halving consumption doubles the distance travelled per litre.
US mpg and UK mpg
The US gallon and imperial gallon are different sizes. An imperial gallon is larger, so the same vehicle receives a higher mpg UK figure than mpg US. Always identify which gallon a review or dashboard is using.
Estimating trip fuel
At 6.5 L/100 km, a 300 km journey uses about 19.5 litres. Multiply that amount by the local fuel price to estimate cost. Real use varies with speed, weather, traffic, load, tyres, terrain, and driving style.
Test figures versus real life
Official laboratory figures are useful for comparing vehicles under common conditions, but they do not predict every journey. For your own average, record several fill-ups and divide fuel added by distance travelled. Using multiple tanks reduces the effect of uneven fill levels.
Use the right source unit
Enter the number exactly as shown and select its unit before converting. If the answer looks surprising, check whether the original was consumption or distance-per-fuel, and whether mpg meant US or imperial. Those two checks explain most large discrepancies.