Part of the Automotive collection — 4 tools available
MPG Calculator — Miles Per Gallon
Calculate your vehicle's real-world miles per gallon from trip data. Enter miles driven and gallons used to find your actual fuel efficiency and cost per mile.
About This Calculator
Your car's window sticker MPG is a laboratory estimate — your actual fuel efficiency depends on driving habits, terrain, cargo weight, tire pressure, weather conditions, and maintenance status. The most accurate way to measure real-world MPG is the fill-up method: fill the tank completely, reset the trip odometer, drive normally, then record miles driven and gallons used at the next fill-up. A single tank can be skewed by highway vs city driving, so averaging 3-4 fill-ups gives the most reliable number. Our MPG calculator does the math and also shows cost per mile.
The Formula Behind This Calculator
MPG = Miles driven / Gallons used Reset trip at fill-up, record gallons at next fill Average over 3+ tanks.
Understanding the math helps you verify results and make better decisions for your project.
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How to Use
- 1Fill your tank completely and reset your trip odometer.
- 2Drive normally until you need fuel again.
- 3Record miles driven and gallons used at your next fill-up.
- 4Enter both numbers plus current gas price.
- 5Click Calculate for real-world MPG and cost per mile.
When to Use
- →Tracking your actual fuel efficiency over time to detect maintenance issues early
- →Comparing real-world MPG between your current car and one you're considering buying
- →Calculating your true cost per mile for tax deductions or mileage reimbursement
Tips
- ✓Average your MPG over 3-4 fill-ups for accuracy — a single tank can be skewed by driving conditions
- ✓A sudden 10-15% MPG drop often signals a maintenance issue like dirty air filter, bad sensors, or low tire pressure
- ✓Use the fill-up method consistently: always fill to the first click and use the same station if possible
FAQ
How do I track MPG accurately?
Use the fill-up method: fill to full, reset trip odometer, drive until near empty, fill to full again, record miles and gallons. Repeat over 3-4 fill-ups and average the results.
Why is my actual MPG lower than the EPA rating?
EPA tests simulate ideal conditions. City driving, AC use, cold starts, roof racks, and aggressive driving all reduce real-world MPG by 10-25% from the sticker number.
What is considered good gas mileage?
Compact cars: 30+ MPG. Sedans: 25-35 MPG. SUVs: 20-30 MPG. Trucks: 15-25 MPG. Hybrids: 40-55 MPG. Anything above average for your vehicle class is good.
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