MPG CalculatorFind your real gas mileage and what each mile costs you
Enter the distance you drove and the fuel it took to refill the tank. You get your real miles per gallon, the metric equivalents, your fuel cost per mile and what a year of driving costs at that rate.
Your fill-up
How to use the MPG Calculator
- Fill the tank completely and reset your trip meter.
- Drive normally until you need fuel again. A full tank gives a more accurate result than a short trip.
- Fill up again and note how many gallons (or liters) it took and the distance on the trip meter.
- Enter both numbers above. Add the fuel price and your yearly mileage to see your cost per mile and yearly fuel spend.
Why your real MPG differs from the window sticker
The EPA rating on a new car’s window sticker comes from lab tests that follow a fixed driving pattern. They are useful for comparing cars, but your own number depends on how, where and when you drive. Most drivers land within about 10% of the combined rating, but some see much bigger gaps in either direction.
The most common reasons your MPG is lower than expected are:
- Short trips. An engine uses much more fuel until it warms up. Trips under 5 miles, especially in cold weather, can cut fuel economy by 15% to 25%.
- Highway speed. Most cars are most efficient between about 45 and 60 mph. Above that, air resistance rises quickly, and every 5 mph over 50 costs several percent in fuel economy.
- Aggressive driving. Hard acceleration and braking waste energy. Smooth driving can improve MPG by 10% to 30% on the highway and in town.
- Idling. An idling engine burns fuel while going nowhere. Long idles at drive-throughs, pick-up lines or to warm the car up all lower your average.
- Tires. Under-inflated tires increase rolling resistance. Larger or all-terrain tires also add weight and drag.
- Extra weight and drag. Roof boxes, bike racks and heavy cargo all cost fuel, especially at highway speed.
- Winter fuel and cold air. Winter-blend gasoline holds slightly less energy, and cold, dense air adds drag.
Typical fuel economy by vehicle type
These are typical real-world ranges for recent gasoline vehicles. Your own car may fall outside them depending on engine, drivetrain and driving style.
| Vehicle type | Typical MPG | L/100km |
|---|---|---|
| Compact car | 30 to 38 | 6.2 to 7.8 |
| Midsize sedan | 28 to 34 | 6.9 to 8.4 |
| Small SUV / crossover | 26 to 32 | 7.4 to 9.0 |
| Midsize SUV | 21 to 27 | 8.7 to 11.2 |
| Full-size pickup | 17 to 23 | 10.2 to 13.8 |
| Hybrid car or SUV | 38 to 55 | 4.3 to 6.2 |
MPG, L/100km and km/L explained
Miles per gallon tells you how far you travel on one gallon, so a higher number is better. Liters per 100 km, used in Canada, Europe and Australia, tells you how much fuel it takes to travel a fixed distance, so a lower number is better. Kilometers per liter is the metric version of MPG and is common in Asia and Latin America.
One thing to watch: US and UK gallons are different sizes. A UK (imperial) gallon is about 20% bigger, so the same car shows a higher MPG figure in the UK. This calculator shows both.
L/100km also makes savings easier to see. Going from 10 to 20 MPG saves far more fuel than going from 30 to 40 MPG, even though both are a 10 MPG gain. In liters per 100 km, the first change is 23.5 to 11.8 (a saving of 11.7 L) and the second is 7.8 to 5.9 (a saving of 1.9 L).
How to improve your gas mileage
- Check tire pressure monthly and keep it at the figure on the driver’s door jamb, not the maximum printed on the tire.
- Drive smoothly. Accelerate gently and look ahead so you can coast to stops instead of braking hard.
- Slow down on the highway. Dropping from 75 to 65 mph often improves fuel economy by 10% or more.
- Remove roof racks and boxes when you are not using them.
- Combine errands so the engine stays warm and you drive fewer cold-start miles.
- Keep up with maintenance. Use the oil grade in your owner’s manual, replace a clogged air filter, and get a check engine light looked at, since a faulty oxygen sensor can cut MPG noticeably.
Why the fill-up method is more accurate than the dashboard
Most cars show an average MPG on the dashboard, but many trip computers read a few percent high. Measuring by fill-ups uses the actual fuel that went into the tank, so it reflects reality. For the best accuracy, use the same pump, let it click off once without topping up, and average your results over three or more tanks.
The formula behind it
L/100km = 235.215 ÷ MPG
km/L = MPG × 0.4251
Cost per mile = Price per gallon ÷ MPG
Yearly cost = Miles per year ÷ MPG × Price per gallon
CO2 is estimated at 8,887 grams per gallon of gasoline burned, the figure the EPA uses for tailpipe emissions. The comparison uses an average of about 27.1 MPG, close to the EPA’s recent real-world estimate for new US vehicles.
Fuel economy facts
Frequently asked questions
How do I calculate my MPG?
What is good gas mileage?
Why is my MPG suddenly lower?
How do I convert MPG to L/100km?
Is the MPG on my dashboard accurate?
Does using the air conditioning lower MPG?
Related tools and guides
Make every tank go further
See our guides to car features and maintenance that affect fuel economy.
Results are estimates for general information only. Always confirm with your owner’s manual, your lender or a qualified technician before acting on them.