⛽ Gas Mileage Calculator
Calculate your vehicle's fuel efficiency (MPG) and fuel costs
📏 Trip Information
📊 Your Results
Fuel Efficiency
Cost per Mile
Total Fuel Cost
Cost per 100 Miles
Annual Estimate
💡 Tips to Improve Fuel Efficiency
- Maintain proper tire pressure
- Avoid aggressive driving and rapid acceleration
- Remove excess weight from your vehicle
- Use cruise control on highways
- Keep your engine properly tuned
- Avoid excessive idling
- Plan trips to avoid heavy traffic
📚 Understanding Gas Mileage
What is Gas Mileage (MPG)?
Gas mileage, measured in Miles Per Gallon (MPG), is the distance your vehicle can travel on one gallon of fuel. It's a key indicator of your vehicle's fuel efficiency and operating costs. Higher MPG means better fuel economy and lower costs per mile.
How to Calculate MPG
The formula for calculating MPG is simple: divide the distance traveled by the amount of fuel used. For example, if you drove 300 miles and used 10 gallons of gas, your MPG would be 30 (300 ÷ 10 = 30 MPG).
Fuel Efficiency Categories
- Poor (0-15 MPG): Large trucks, SUVs, or older vehicles with poor maintenance
- Below Average (15-20 MPG): Full-size vehicles, performance cars, or city driving
- Average (20-30 MPG): Most modern sedans and crossovers
- Good (30-40 MPG): Fuel-efficient cars, hybrids, or highway driving
- Excellent (40+ MPG): Hybrid vehicles, electric vehicles, or highly efficient cars
Factors Affecting Gas Mileage
- Driving Habits: Aggressive acceleration and braking reduce efficiency by up to 33%
- Speed: Gas mileage decreases rapidly above 50 mph
- Vehicle Maintenance: Proper maintenance can improve MPG by up to 4%
- Tire Pressure: Under-inflated tires can lower MPG by 0.2% for every 1 psi drop
- Weight: Extra 100 pounds can reduce MPG by about 1%
- Aerodynamics: Roof racks and open windows increase drag
- Weather: Cold weather and air conditioning use reduce efficiency
- Terrain: Hills and mountains require more fuel than flat roads
Tips for Accurate Measurement
- Fill your tank completely at the start and end of measurement
- Record your odometer reading when you fill up
- Drive normally for at least one full tank
- Calculate MPG over multiple fill-ups for better accuracy
- Keep track of city vs. highway driving separately
- Note any unusual conditions (weather, traffic, cargo)
How to Improve Your Gas Mileage
- Drive Smoothly: Avoid rapid acceleration and hard braking
- Maintain Speed: Use cruise control on highways
- Reduce Idling: Turn off engine if stopped for more than 30 seconds
- Check Tire Pressure: Keep tires inflated to recommended PSI
- Regular Maintenance: Change oil, air filters, and spark plugs on schedule
- Lighten the Load: Remove unnecessary items from your vehicle
- Plan Routes: Combine errands and avoid rush hour
- Use Recommended Oil: Use the manufacturer's recommended grade
Frequently Asked Questions
What is considered good gas mileage?
Good gas mileage depends on the vehicle type. For sedans, 30-40 MPG is considered good. For SUVs and trucks, 20-25 MPG is good. Hybrid vehicles can achieve 40-50+ MPG. Compare your vehicle's MPG to its EPA rating for your specific model.
How do I calculate MPG manually?
Fill your tank completely and record the odometer reading. Drive normally until you need to refuel. Fill the tank again and note how many gallons it took and your new odometer reading. Subtract the old odometer reading from the new one to get miles driven, then divide by gallons used.
Why is my actual MPG lower than the EPA rating?
EPA ratings are tested under ideal laboratory conditions. Real-world factors like traffic, weather, terrain, driving habits, vehicle load, and maintenance affect your actual MPG. City driving typically gets lower MPG than highway driving. Aggressive driving can reduce MPG by up to 33%.
Does air conditioning affect gas mileage?
Yes, air conditioning can reduce fuel economy by 5-25% depending on usage. At highway speeds, using AC is more efficient than opening windows (which increases drag). In city driving, opening windows may be more efficient. Use AC moderately and park in shade when possible.
How much can proper tire pressure improve MPG?
Properly inflated tires can improve gas mileage by up to 3%. Under-inflated tires increase rolling resistance, making your engine work harder. Check tire pressure monthly and before long trips. Inflate to the pressure recommended in your owner's manual or on the driver's door jamb sticker.
What's the difference between city and highway MPG?
Highway MPG is typically 20-30% higher than city MPG. City driving involves frequent stops, starts, and idling, which consume more fuel. Highway driving maintains steady speeds, which is more efficient. Combined MPG is a weighted average of 55% city and 45% highway driving.
Can driving slower improve gas mileage?
Yes, gas mileage typically peaks at 50-60 mph and decreases rapidly above that. For every 5 mph over 50 mph, you pay an additional $0.20 per gallon equivalent. Reducing highway speed from 70 to 60 mph can improve fuel economy by 7-14%. Use cruise control to maintain steady speeds.