Enter your miles driven and gallons used to instantly calculate your car's real-world fuel economy. Find out if your car is performing as well as it should.
Open Full MPG CalculatorMPG (miles per gallon) tells you how far your car travels on one gallon of gas. The formula is simple:
Step 1: Fill your tank completely until the pump clicks off automatically. Note your current odometer reading or reset your trip odometer to zero.
Step 2: Drive normally for a full tank — at least 200 miles for an accurate reading. Mix of city and highway driving gives the most representative result.
Step 3: When your tank is low (but not empty), return to a gas station and fill up completely again. Note exactly how many gallons it took.
Step 4: Note how many miles you drove (from your trip odometer or by subtracting your starting odometer from your current reading). Divide miles by gallons — that's your real MPG.
How does your fuel economy compare? Here's the average MPG for common vehicle types:
| Vehicle Type | City MPG | Highway MPG | Combined MPG | Rating |
|---|---|---|---|---|
| Hybrid Sedan | 43–52 | 41–48 | 42–50 | Excellent |
| Compact Car | 28–35 | 36–42 | 30–38 | Good |
| Mid-Size Sedan | 22–28 | 30–38 | 25–32 | Good |
| Crossover SUV | 22–28 | 28–34 | 24–30 | Average |
| Full-Size SUV | 14–20 | 18–24 | 16–22 | Below Avg |
| Pickup Truck | 14–19 | 18–23 | 15–21 | Below Avg |
| Sports Car | 14–20 | 20–28 | 16–22 | Below Avg |
| Full-Size Truck | 13–17 | 16–21 | 14–18 | Poor |
Under-inflated tires are one of the most common causes of poor fuel economy. For every 1 PSI drop below the recommended pressure, you lose about 0.2% MPG. Check monthly — the correct pressure is on the sticker inside your driver's door jamb, not the number printed on the tire itself.
A clogged air filter restricts airflow to the engine, forcing it to burn more fuel to produce the same power. Replacing a dirty air filter can improve MPG by up to 10% on older vehicles. Most manufacturers recommend replacing it every 15,000–30,000 miles.
Worn spark plugs misfire, wasting fuel that doesn't ignite properly. This can reduce MPG by 4–30% according to the National Institute for Automotive Service Excellence. Most spark plugs should be replaced every 30,000–100,000 miles depending on type.
Aerodynamic drag increases exponentially with speed. Driving at 75 mph instead of 65 mph uses about 20% more fuel. The sweet spot for most vehicles is 50–65 mph — beyond that, you're fighting air resistance more than you're saving time.
Idling burns fuel at 0 MPG. A modern fuel-injected engine uses very little gas to restart — less than 30 seconds of idling in most cases. If you're parked or waiting more than a minute, turning off the engine saves fuel and reduces wear.
Every 100 lbs of extra weight reduces fuel economy by about 1%. Remove heavy items you don't need: toolboxes, sports equipment, sandbags. Remove roof cargo carriers when not in use — they add significant aerodynamic drag even when empty.