MPG / Fuel Economy Calculator
Find your vehicle's real-world fuel economy. Track fill-up to fill-up MPG, convert between imperial and metric fuel economy, and compare against EPA estimates.
1. Calculate Your MPG
2. Convert Fuel Economy
Edit any field — the others update automatically.
3. Compare to EPA Estimate
How to use MPG / Fuel Economy Calculator
The MPG calculator computes your vehicle's real-world fuel economy from fill-up data: miles driven and gallons used. It also converts between MPG (US), MPG (UK/imperial), L/100km and km/L so you can compare vehicles across international specifications, and lets you track multiple fill-ups to spot trends.
- Fill up your tank, reset the trip odometer.
- Drive normally, then fill up again — note miles driven and gallons added.
- Enter both values and click Calculate.
- Convert the result to any other fuel economy unit.
- Add multiple fill-ups to track average fuel economy over time.
Your data never leaves your device — 100% private processing.
MPG formula and unit conversions
US MPG = miles ÷ gallons. To convert: L/100km = 235.215 ÷ US MPG; UK MPG = US MPG × 1.20095 (UK gallon is larger); km/L = US MPG × 0.425144. These conversions are important when comparing European (L/100km) cars with US (MPG) ratings or using imported vehicles with UK specifications.
| US MPG | UK MPG | L/100km | km/L |
|---|---|---|---|
| 20 | 24.0 | 11.8 | 8.5 |
| 30 | 36.0 | 7.8 | 12.8 |
| 40 | 48.0 | 5.9 | 17.0 |
| 50 | 60.0 | 4.7 | 21.3 |
| 60 | 72.1 | 3.9 | 25.5 |
Vehicle class fuel economy benchmarks (EPA)
Real-world MPG varies widely by vehicle class. Compact cars (Honda Civic, Toyota Corolla) achieve 30–38 MPG combined. Midsize sedans reach 28–35 MPG. SUVs range from 22–30 MPG. Full-size trucks: 15–22 MPG. Hybrids (Toyota Prius, Hyundai Ioniq): 45–60 MPG. Plug-in hybrids: 40–55 MPG on gas. Comparing your fill-up MPG to the EPA estimate tells you whether your driving style and conditions are average, better or worse.
Glossary
- MPGe
- Miles per gallon equivalent — used for electric vehicles, where 33.7 kWh equals one gallon of petrol.
- Combined MPG
- A weighted average of city (55%) and highway (45%) fuel economy used for EPA window stickers.
- Trip odometer
- A resettable odometer used to track miles for a specific fill-up interval.
- Fuel economy
- The distance a vehicle travels per unit of fuel; higher MPG = more fuel-efficient.
Related reading
Frequently Asked Questions
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Why use MPG / Fuel Economy Calculator?
- Covers all major auto loan and leasing calculations
- Fuel cost comparisons with real MPG/L/100km data
- Instant results with no spreadsheet required
- Supports both metric and imperial units
Common use cases
- Calculate monthly payments on a car loan
- Compare the total cost of owning vs leasing
- Estimate annual fuel costs for a vehicle
- Calculate depreciation over 5 years
- Find out true cost of ownership including insurance
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