This Template formats mpg into MPGe_US and L/100 km

• units: mpgus, mpgimp, l/100 km, mi/BTU, mi/kwh, kWh/100 km, MJ/km, etc. and
• fuel (or source): gasoline, petrol, diesel, jetK, heat, electric, etc.

• Gas/100 km=litres Diesel per hundred kilometres
• Diesel/100 km=litres Diesel per hundred kilometres
• JetK/100 km=litres Jet fuel per hundred kilometres
• kWh/100 km=kWh per hundred kilometres
• BTU/100 km=BTU per hundred kilometres
• mi/USGas=miles per US gallon of Gasoline
• mpgus=miles per US gallon of Gasoline
• mi/USDiesel=miles per US gallon of Diesel
• mi/USJetK=miles per US gallon of Jet Fuel (Kerosene)
• mi/BTU=miles per BTU
• mi/kWh=miles per kWh
• mi/ImpGas=miles per Imp gallon of Diesel
• mi/ImpDiesel=miles per Imp gallon of Diesel
• mi/ImpJetK=miles per Imp gallon of Jet Fuel (Kerosene)

Usage:

• {{MPGe|10|mpgus|lk=on}}:

10 L /100 km (10 MPGe US)

• {{MPGe|10|mpgus}}:

10 L /100 km (10 MPGe US)

• {{MPGe|50|mpgus|3}}:

50 L /100 km (50 MPGe US)

• {{MPGe|10|mpgus|p=on}}:

10 L /100 p·km (10 p·MPGe US)

Options:

• The second parameter is decimal precision (default 1 decimal)
• p=on adds p· for passenger miles
• Make units wikilinked by attaching |lk=on.

  The manual of style suggests that you only link the first instance.