Gas Mileage Calculator – MPG from Fill-up
Calculate your car's actual MPG from odometer readings and gallons filled.
About This Calculator
Calculate your car's actual MPG from odometer readings and gallons filled. Use the calculator above for instant results.
Worked Examples
- 350/11 = 31.8 MPG
Answer: 31.8 MPG
- 250/12.5 = 20 MPG
Answer: 20 MPG
- 450/9 = 50 MPG
Answer: 50 MPG
Who Uses This Calculator?
Track your real-world fuel economy.
Measure efficiency of different vehicles.
Calculate monthly fuel cost.
Monitor vehicle efficiency.
Common Mistakes to Avoid
❌ Not filling completely
Always fill to the same level (full) for accurate calculation. Partial fill-ups skew the MPG calculation.
❌ Short trips have worse MPG
Cold starts and short trips (under 5 miles) reduce MPG significantly. Long highway drives show best fuel economy.
Frequently Asked Questions
Average US car MPG?
New cars average ~28 MPG. SUVs/trucks: 20-25. Sedans: 28-35. Hybrids: 40-55. EVs: equivalent 90-130 MPGe.
What affects MPG?
Speed (>65mph hurts), AC, tire pressure (low = worse), cold weather, driving style (aggressive = worse), payload.
Cost per mile?
Divide gas price by MPG. $4 gas / 30 MPG = $0.133/mile.