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4. Driver tools

Driving your car Driver tools

Want to work out your car's true mpg, or whether you'll be better off with a diesel car? Our interactive tools make doing the sums easy.

Fuel economy calculator

How efficient is your car? Here's how to check your mpg

Petrol vs diesel

Which is cheaper to run? We do the sums so you don't have to

Power converter: bhp, PS and kW

Convert quickly and easily between bhp, kW and PS.

Litres to gallons converter

Quick litres-to-gallons conversion tool from Which?

• Speed converter (mph to kmh and kmh to mph)

  

  Free speed calculator tool

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