Fuel Consumption Converter — Convert km/L, MPG, L/100km & More
Our free online fuel consumption converter instantly converts between all major fuel economy units: kilometers per liter (km/L), miles per gallon US (MPG), miles per gallon UK (Imperial MPG), liters per 100 kilometers (L/100km), and miles per liter. Whether you're comparing car specifications from different countries, calculating road trip fuel costs, or evaluating vehicle efficiency for purchase decisions, this tool provides accurate conversions with real-world context.
What is Fuel Consumption?
Fuel consumption (also called fuel economy or mileage) measures how efficiently a vehicle uses fuel. It can be expressed in two ways: distance per volume (km/L, MPG — higher is better) or volume per distance (L/100km — lower is better). The choice of unit varies by country and region.
Understanding fuel consumption helps you estimate travel costs, compare vehicles during purchase, track your car's health (declining mileage may indicate maintenance issues), and make environmentally conscious choices. A car consuming 5 L/100km produces approximately 115 g/km of CO₂, while one consuming 10 L/100km produces about 230 g/km.
Fuel Economy Units Explained
| Unit | Type | Used In | Better Efficiency = |
|---|---|---|---|
| km/L | Distance/Volume | India, Japan, Korea, Brazil | Higher number |
| MPG (US) | Distance/Volume | United States | Higher number |
| MPG (UK/Imperial) | Distance/Volume | United Kingdom | Higher number |
| L/100km | Volume/Distance | Europe, Australia, Canada | Lower number |
| mi/L | Distance/Volume | Niche/cross-system | Higher number |
Key Conversion Formulas
- km/L to MPG (US): MPG = km/L × 2.35215
- MPG (US) to km/L: km/L = MPG ÷ 2.35215
- km/L to L/100km: L/100km = 100 ÷ km/L
- L/100km to km/L: km/L = 100 ÷ L/100km
- MPG (US) to L/100km: L/100km = 235.215 ÷ MPG
- L/100km to MPG (US): MPG = 235.215 ÷ L/100km
- km/L to MPG (UK): MPG(UK) = km/L × 2.82481
- MPG (US) to MPG (UK): MPG(UK) = MPG(US) × 1.20095
- km/L to mi/L: mi/L = km/L × 0.621371
Fuel Efficiency Comparison Table — Vehicle Types
| Vehicle Type | km/L | MPG (US) | L/100km |
|---|---|---|---|
| Economy hatchback (petrol) | 18–23 | 42–54 | 4.3–5.6 |
| Mid-size sedan (petrol) | 14–18 | 33–42 | 5.6–7.1 |
| Compact SUV (diesel) | 16–22 | 38–52 | 4.5–6.3 |
| Full-size SUV | 8–13 | 19–31 | 7.7–12.5 |
| Hybrid sedan | 22–28 | 52–66 | 3.6–4.5 |
| Plug-in Hybrid (PHEV) | 25–50+ | 59–117+ | 2.0–4.0 |
| Sports car | 7–12 | 16–28 | 8.3–14.3 |
| Motorcycle (150cc) | 40–60 | 94–141 | 1.7–2.5 |
Tips to Improve Fuel Efficiency
🚗 Driving Habits
Smooth acceleration and braking can improve mileage by 15-30%. Avoid rapid starts, maintain steady speeds, use cruise control on highways, and anticipate traffic to reduce unnecessary braking. The optimal fuel-efficient speed for most cars is 55-80 km/h (35-50 mph).
🔧 Vehicle Maintenance
A well-maintained engine runs 10-20% more efficiently. Keep tire pressure at recommended levels (under-inflated tires increase rolling resistance by 3-5%), change air filters regularly, use recommended oil grade, and ensure wheel alignment is correct.
📦 Reduce Load & Drag
Every 50 kg of extra weight reduces fuel economy by about 1-2%. Remove roof racks when not in use (they increase drag by 5-25% at highway speeds), clear unnecessary items from the trunk, and keep windows closed at high speeds to reduce aerodynamic drag.
🌡️ Environmental Factors
Air conditioning can reduce mileage by 5-15% in city driving. In moderate weather, use ventilation instead. Cold engines consume more fuel — combine short trips when possible. Plan routes to avoid traffic congestion and excessive idling.
Understanding US vs. UK MPG
One of the most common sources of confusion in fuel economy is the difference between US MPG and UK (Imperial) MPG. The US gallon contains 3.785 liters while the Imperial gallon contains 4.546 liters — making the Imperial gallon about 20% larger. This means:
- A car rated 40 MPG (UK) is actually 33.3 MPG (US) = 14.2 km/L
- A car rated 30 MPG (US) is actually 36 MPG (UK) = 12.75 km/L
- UK figures always appear higher for the same car — don't be deceived when comparing international reviews
- When in doubt, convert everything to L/100km or km/L for a fair, universal comparison
Fuel Cost Calculation Example
Understanding fuel consumption helps calculate trip costs. Here's a practical example:
Scenario: Drive 500 km in a car that gets 15 km/L, fuel price ₹105/liter
Fuel needed = 500 km ÷ 15 km/L = 33.33 liters
Cost = 33.33 × ₹105 = ₹3,500
Same trip in a 20 km/L car: 25 liters × ₹105 = ₹2,625 (saving ₹875)
Frequently Asked Questions (FAQ)
1. How do you convert km/L to MPG?
Multiply km/L by 2.35215 to get MPG (US), or by 2.82481 to get MPG (UK/Imperial). For example, 15 km/L × 2.35215 = 35.28 MPG (US). The difference between US and UK MPG is due to different gallon sizes (US gallon = 3.785L, UK gallon = 4.546L).
2. What is the difference between MPG US and MPG UK?
The US gallon (3.785 liters) is smaller than the UK Imperial gallon (4.546 liters). So 1 MPG (UK) = 1.201 MPG (US). A car advertised as "50 MPG" in the UK would be about 41.6 MPG by US standards. Always verify which system is being referenced.
3. How do I convert L/100km to km/L?
Use the formula: km/L = 100 ÷ L/100km. They are inverse relationships. For example, 6.5 L/100km = 100 ÷ 6.5 = 15.38 km/L. Remember: lower L/100km = better efficiency, while higher km/L = better efficiency.
4. What is considered good fuel economy?
It depends on vehicle type: Economy cars should achieve 15-23 km/L (35-54 MPG). SUVs typically get 10-15 km/L (23-35 MPG). Hybrids achieve 22-28 km/L (52-66 MPG). In India, 15-20 km/L for petrol cars and 18-25 km/L for diesel is considered good.
5. Why do different countries use different fuel economy units?
It's historical: the US uses miles and gallons (MPG), Europe adopted metric volume-per-distance (L/100km) for easier cost calculation, and countries like India and Japan use distance-per-volume (km/L) in metric units. The EU and many countries are standardizing on L/100km and WLTP testing.
6. How can I improve my car's fuel efficiency?
Key strategies: maintain proper tire pressure, drive smoothly (avoid aggressive acceleration/braking), keep speed moderate (55-80 km/h optimal), reduce vehicle weight, remove roof racks, use cruise control, keep engine maintained, avoid excessive idling, and combine short trips when possible.
7. What affects fuel consumption the most?
The biggest factors are: driving style (can vary consumption by 30%+), speed (fuel use increases exponentially above 90 km/h), vehicle weight, aerodynamic drag, stop-and-go traffic, terrain, tire pressure, air conditioning use, and engine condition. City driving typically uses 30-50% more fuel than highway driving.
8. How do electric vehicles compare in efficiency?
EVs use km/kWh or Wh/km instead of km/L. Typical EVs achieve 5-7 km/kWh. In energy-equivalent terms, this is roughly 50-80 km/L equivalent (120-190 MPGe), making EVs 3-4x more efficient than combustion engines. However, electricity costs per km vary by region and charging method.