Kilometers per Gallon (US) (km/gal (US)) - Unit Information & Conversion

Definition

Kilometers per Gallon (US), often abbreviated as km/gal (US), is a unit of fuel efficiency. It measures the distance in kilometers (km) that a vehicle can travel using one US liquid gallon (US gal) of fuel. It combines a metric unit of distance with a US customary unit of volume.

History

This unit is not a standard international or US unit for fuel consumption. Its use typically arises in specific, often informal, contexts where metric distances (kilometers) need to be related to fuel volumes measured in US gallons. This might occur when comparing vehicle specifications or fuel data between regions using different systems (e.g., comparing a European car's potential range using US fuel measurements) or during transitions between measurement systems.

Common Uses

Kilometers per Gallon (US) is rarely used in official vehicle specifications, regulations, or everyday conversation, especially within the United States where Miles per Gallon (US MPG) is the standard. Globally, Liters per 100 kilometers (L/100km) or Kilometers per Liter (km/L) are more common metric standards. Its primary use might be in specific technical calculations, data conversions, or informal comparisons involving US fuel volumes alongside metric distances.

Unit FAQs

Why is km/gal (US) not commonly used?

The United States primarily uses Miles per Gallon (US MPG) for vehicle fuel efficiency. Most other countries using the metric system prefer Kilometers per Liter (km/L) or Liters per 100 Kilometers (L/100km). Hybrid units like km/gal (US) mix systems and are generally avoided in official standards to prevent confusion.

How does km/gal (US) differ from km/gal (UK)?

The key difference is the gallon size. The US liquid gallon is smaller than the Imperial (UK) gallon (1 US gallon ≈ 3.785 liters, while 1 UK gallon ≈ 4.546 liters). Therefore, for the same actual fuel efficiency, a vehicle's rating in km/gal (US) will be numerically higher than its rating in km/gal (UK) because it travels the same distance using a smaller gallon measure.

How do I convert km/gal (US) to km/L?

Divide the value in km/gal (US) by the exact number of liters in a US gallon: km/L = km/gal (US) / 3.785411784.

How do I convert km/gal (US) to MPG (US)?

Divide the value in km/gal (US) by the exact number of kilometers in a mile: MPG (US) = km/gal (US) / 1.609344.

How do I convert km/gal (US) to the common L/100km format?

Use the inverse relationship formula: L/100km = 378.5411784 / km/gal (US). A higher km/gal (US) value corresponds to a lower L/100km value (indicating better fuel economy).