How Far Will £X Take You?

Ever found yourself at motorway services wondering how far a £20 top-up will get you? This calculator tells you exactly how many miles you can cover for a given spend, based on your car's MPG and the current fuel price.

For the most accurate result, use our MPG Calculator to establish your real-world MPG first. The manufacturer's figure is typically 20–30% higher than reality.

Need to know the current fuel price? Use our fuel station finder to look up live prices near you.

Calculate your Distance covered for a given cost of fuel

Enter your figures above and click Calculate to see your result.

How the distance calculation works

The calculator reverses the normal fuel cost formula — instead of "how much will X miles cost?", it answers "how far will £X take me?":

Distance (miles) = (budget ÷ price per litre) ÷ 4.54609 × MPG

Your budget buys a certain number of litres. Divide by 4.54609 to convert to imperial gallons. Multiply gallons by your MPG and you get the miles you can cover.

Example: £30 budget, fuel at 142p per litre, car doing 42 MPG. £30 buys 21.13 litres = 4.65 gallons. 4.65 × 42 = 195 miles.

Getting more miles from your money

There are two sides to this equation — paying less per litre and using less fuel per mile:

  • Fill up at supermarkets — Asda, Tesco, Sainsbury's and Morrisons are consistently cheaper than branded and motorway stations. Use our fuel station finder to compare live prices near you.
  • Avoid motorway services — service station fuel typically costs 10–15p per litre more. On a £40 fill-up, that's 2–3 fewer litres and 20–30 fewer miles.
  • Slow down — cruising at 60 mph instead of 70 mph improves fuel economy by 10–15%, adding meaningful range on a long drive.
  • Check tyre pressures — underinflated tyres increase rolling resistance. Correct pressures can add 2–3 MPG to your real-world figure.
  • Reduce drag and weight — remove roof racks and clear unnecessary weight from the boot. Less resistance means more miles per gallon.

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Frequently Asked Questions

It depends entirely on your car's MPG and the current fuel price. A car doing 55 MPG will travel roughly 40% further on the same £20 than one doing 35 MPG. Enter your figures into the calculator above for an exact answer based on today's prices.

The calculator divides your budget by the price per litre to get litres of fuel, converts litres to imperial gallons (dividing by 4.546), then multiplies by your MPG to get the distance in miles.

Motorway service stations have higher operating costs, a captive audience and less local competition, so they typically charge 10–20p per litre more than supermarkets or town centre stations. Our fuel station finder shows the premium in real time.

Yes. Aerodynamic drag increases with the square of speed, so driving at 80 mph uses significantly more fuel per mile than 60 mph. For maximum range from a fixed budget, steady driving at 60–65 mph is typically most efficient.

Keep tyres at the correct pressure, drive smoothly, avoid high speeds, remove roof racks and reduce unnecessary weight. Filling up at a cheaper station also means more litres for the same money — check our fuel station finder for the best prices near you.

Always use your real-world MPG. Manufacturer figures are 15–25% higher than what you'll see in everyday driving. Using the official figure will overestimate your range. Measure your true MPG with our MPG calculator.