Vehicle Fuel Efficiency Calculator | MPG & L/100km Converter
Total distance covered since last refuel
Amount of fuel added during refuelling
💡 Efficiency Tips
- Maintain steady speeds on motorways
- Service your vehicle regularly
- Check tyre pressures monthly
- Remove unnecessary weight from your boot
- Plan journeys to avoid traffic congestion
- Consider car sharing for regular commutes
📊 Understanding MPG
- Higher MPG means better fuel efficiency
- City driving typically yields lower MPG
- Highway driving is usually more efficient
- Weather conditions can affect efficiency
Glossary of Terms
Tank Range
The estimated distance a vehicle can travel on a full tank of fuel, determined by its fuel efficiency.
Driving Style
How a driver operates the vehicle (e.g., smooth acceleration, heavy braking), which can significantly impact fuel efficiency.
Urban Driving
Driving in city environments characterised by frequent stops and starts, typically leading to lower fuel efficiency.
Idle Time
The period when the engine is running but the vehicle is stationary, consuming fuel without contributing to distance travelled.
Frequently Asked Questions
How does air conditioning affect fuel consumption?
Using the air conditioning in your car increases fuel consumption, particularly at low speeds, because it adds extra load on the engine. However, at higher speeds, rolling down the windows can create drag and reduce efficiency even more than using the air conditioning.
Why does fuel efficiency decrease in heavy traffic?
In heavy traffic, frequent stopping and starting can significantly increase fuel consumption because the engine uses more fuel to accelerate repeatedly. Additionally, idling wastes fuel, as the engine continues to burn fuel even when the vehicle is not moving.
Does idling use more fuel than restarting the engine?
In modern vehicles, idling for more than 10 seconds uses more fuel than restarting the engine. This is why start-stop systems are designed to be fuel-efficient—they automatically shut off the engine when the vehicle is stationary and restart it when you're ready to move, helping to save fuel and reduce emissions.
Why does fuel efficiency decrease with age?
As vehicles age, wear and tear on engine components can lead to reduced fuel efficiency. However, regular maintenance can help mitigate these effects by ensuring that the engine and other critical systems are functioning optimally. Keeping up with oil changes, air filter replacements and other routine checks can significantly enhance a vehicle's performance and fuel economy over time.
How does driving speed affect fuel efficiency?
Fuel efficiency typically peaks at moderate speeds, around 50 to 60 mph. Driving too fast can lead to increased wind resistance, whilst driving too slowly may result in engine inefficiency. Maintaining a steady speed within this optimal range helps maximise fuel economy and reduces overall fuel consumption.
How does weather affect fuel consumption?
Cold weather can negatively affect fuel efficiency because engines take longer to warm up, and using heaters can increase fuel consumption. Similarly, hot weather can impact efficiency as drivers tend to rely more on air conditioning, which also uses additional fuel.