MPG to L/100 km Converter
Convert fuel economy from miles per gallon (MPG) to liters per 100 kilometers (L/100 km) instantly.
Common Conversions (US MPG → L/100km)
| MPG | L/100km |
|---|---|
| 20 | 11.76 |
| 25 | 9.41 |
| 30 | 7.84 |
| 35 | 6.72 |
| 40 | 5.88 |
How the MPG to L/100 km Conversion Works
Fuel economy is measured differently depending on where you live. In the United States and the United Kingdom, fuel consumption is expressed as miles per gallon (MPG). In most other countries, including those in Europe, Canada, Australia, and New Zealand, fuel efficiency is measured in liters per 100 kilometers (L/100 km).
The conversion between these two units is not a simple multiplication. Because MPG measures distance per volume (how far you can travel on a gallon of fuel) and L/100 km measures volume per distance (how much fuel is needed to travel 100 km), the relationship is inverse.
The formula used for this conversion is:
L/100 km = 282.48 ÷ MPG (US)
For UK (imperial) gallons, the formula uses a different constant:
L/100 km = 235.21 ÷ MPG (UK)
This tool automatically applies the correct formula based on whether you select US or UK gallons.
How to Use the Converter
- Enter your vehicle's fuel economy value in the MPG input field.
- Select whether you are using US gallons or UK (imperial) gallons from the dropdown menu.
- The converted value in L/100 km will update instantly as you type.
No button clicking is required. The conversion happens in real time as you adjust the input or change the gallon type.
Understanding Your Results
The result shows how many liters of fuel your vehicle consumes to travel 100 kilometers. A lower L/100 km value means better fuel economy. A higher value means worse fuel economy.
For reference:
- 30 MPG (US) = approximately 9.4 L/100 km
- 40 MPG (US) = approximately 7.1 L/100 km
- 50 MPG (US) = approximately 5.6 L/100 km
If you are comparing vehicles from different markets, always check whether the MPG figure is based on US or UK gallons. A UK gallon is about 20% larger than a US gallon, so the same vehicle will show a higher MPG rating under the UK system.
Practical Use Cases
Comparing Vehicles Across Markets
If you are importing a car from the US to Europe or Canada, you need to convert the advertised MPG to L/100 km to understand real-world fuel costs in your local measurement system.
Evaluating Fuel Costs
Knowing your vehicle's L/100 km value allows you to calculate fuel costs per kilometer or per trip. Multiply the L/100 km figure by your local fuel price per liter, then divide by 100 to get the cost per kilometer.
Understanding Manufacturer Specifications
Many car manufacturers list fuel economy in both MPG and L/100 km in their technical specifications. This converter helps you verify those numbers or convert figures from one system to the other.
Common Mistakes When Converting MPG to L/100 km
Using the Wrong Gallon Type
The most frequent error is using the US gallon formula when the MPG value is based on UK gallons, or vice versa. This can result in a conversion error of approximately 20%. Always confirm which gallon standard applies to your MPG figure.
Confusing MPG with L/100 km Direction
Remember that a higher MPG value means better fuel economy, while a lower L/100 km value means better fuel economy. The relationship is inverse. A common mistake is to assume that doubling MPG halves L/100 km, which is not accurate due to the inverse relationship.
Rounding Too Early
If you are performing the conversion manually, rounding the intermediate result too early can introduce noticeable errors. This tool handles the calculation with full precision and rounds only the final displayed result.
FAQ
What is the difference between US MPG and UK MPG?
A US gallon is 3.785 liters, while a UK (imperial) gallon is 4.546 liters. Because the UK gallon is larger, the same vehicle will achieve a higher MPG rating when measured in UK gallons. This means the conversion constant is different for each system.
Is a higher MPG always better?
Yes. A higher MPG value means the vehicle can travel more miles on a single gallon of fuel, indicating better fuel efficiency. When converted to L/100 km, a higher MPG will produce a lower L/100 km value.
Can I convert L/100 km back to MPG with this tool?
This tool converts MPG to L/100 km. To convert in the opposite direction, you would need a separate L/100 km to MPG converter, which uses the same formulas but solves for MPG instead.
Why does my car's manual show both MPG and L/100 km?
Many vehicles sold in global markets display both units to accommodate drivers who travel internationally or to simplify comparisons across different measurement systems. The manual typically specifies which gallon standard is used.