**How much petrol do I need for 100 miles?** If you have a long journey coming up, or you’re simply curious to know how much petrol you’ll need to drive **100 miles**, the petrol calculator below will work out the amount of petrol needed and an estimated **petrol cost for 100 miles** based on your **MPG.**

The calculator is set to **100 miles by default,** but you can change this if you wish. Also, the calculator will display both litres and UK gallons of petrol required.

Don’t know your vehicle’s real MPG? Use this MPG calculator to find out your vehicle’s exact miles per gallon consumption figure.