Miles per Gallon (UK) (MPG (UK)) - Unit Information & Conversion

Definition

Miles per Gallon (UK), often abbreviated as MPG (UK) or simply MPG in the UK context, is a unit of fuel efficiency used primarily within the Imperial system. It quantifies the distance in miles that a vehicle can travel using one Imperial gallon of fuel. A higher MPG (UK) value indicates better fuel efficiency.

History

The Imperial gallon was defined in the UK Weights and Measures Act of 1824 and became the standard measure for liquids. Consequently, MPG based on this gallon became the traditional measure of vehicle fuel efficiency in the United Kingdom and several Commonwealth countries. While the metric unit L/100km is now also used officially (especially for new car regulations and comparisons), MPG (UK) remains deeply ingrained in public understanding and is widely used by consumers and in the media.

Common Uses

• Consumer Vehicle Choice (UK): A primary factor for UK consumers when comparing the running costs and environmental impact of different vehicles.
• Manufacturer Advertising (UK): Often highlighted in car advertisements and brochures targeting the UK market.
• Used Car Sales (UK): Frequently quoted figure when evaluating and selling pre-owned vehicles.
• Fuel Cost Estimation: Used by drivers to estimate fuel consumption and costs for journeys.
• Informal Benchmarking: Common unit used in everyday conversation about car performance in the UK.

Unit FAQs

How is MPG (UK) different from MPG (US)?

The core difference is the gallon size. The Imperial gallon (UK) is larger than the US customary gallon (approximately 4.546 liters vs. 3.785 liters). Because a vehicle travels the same distance but the UK gallon contains more fuel, the MPG (UK) figure for a given vehicle will always be higher than its MPG (US) figure. Specifically, 1 MPG (UK) ≈ 1.201 MPG (US).

Is a higher MPG (UK) value better?

Yes, a higher MPG (UK) value signifies better fuel efficiency. It means the vehicle can cover more miles for each Imperial gallon of fuel consumed.

How do I convert MPG (UK) to L/100km?

To convert Imperial Miles Per Gallon to Liters per 100 kilometers, use the formula: L/100km ≈ 282.48 / MPG (UK). Note that unlike MPG, a lower L/100km value indicates better fuel efficiency.

How do I convert MPG (UK) to MPG (US)?

To convert Imperial Miles Per Gallon to US Miles Per Gallon, use the formula: MPG (US) ≈ MPG (UK) * 0.83267.

How do I convert MPG (UK) to km/L?

To convert Imperial Miles Per Gallon to Kilometers per Liter, use the formula: km/L ≈ MPG (UK) * 0.3540. Like MPG, a higher km/L value indicates better fuel efficiency.