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Last updated: June 1, 2026

MPG Calculator: Miles Per Gallon

Calculate your vehicle's fuel economy by entering the miles driven and gallons used. Track your MPG over time to spot changes in fuel efficiency and identify maintenance needs.

Enter Trip Data

Fuel Economy

Miles Per Gallon25.0MPG
Liters per 100km9.4L/100km
Cost Per Mile$0.140(at $3.50/gal)
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Understanding the MPG Calculator

An MPG (miles per gallon) calculator measures your vehicle’s real-world fuel efficiency from the miles you drove and the fuel you used. Tracking your actual mileage — rather than relying on the sticker estimate — reveals how your driving, maintenance, and conditions affect what you spend at the pump.

How to measure it accurately

Fill the tank completely and note your odometer. Drive normally until you need fuel again, then fill up and record the miles traveled and gallons added. Dividing miles by gallons gives your MPG for that tank. Measuring across several tanks smooths out variation and gives a more reliable average.

What hurts your fuel economy

Aggressive acceleration, high speeds, excess idling, under-inflated tires, and carrying extra weight all lower MPG. Short trips, where the engine never fully warms up, are especially inefficient. Tracking your numbers helps you spot a sudden drop, which can signal a maintenance issue like a clogged filter or failing sensor.

Tips & things to know

  • Average several tanks for a reliable figure.
  • Proper tire pressure and gentle acceleration improve MPG.
  • A sudden drop can indicate a maintenance problem.

Formula

MPG = Miles Driven ÷ Gallons Used

Example: 350 miles ÷ 14 gallons = 25 MPG

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How to Use the MPG Calculator

1

Open the MPG Calculator

Navigate to the MPG Calculator page on Redicalc. The calculator loads instantly with no sign-up required.

2

Enter your values

Fill in vehicle specifications such as engine size, fuel usage, or tire dimensions. Toggle between metric and imperial units if available.

3

Review your results

Your mpg results appear instantly as you type. Review the breakdown, charts, or detailed analysis provided.

4

Adjust and compare

Try different input values to compare scenarios. This helps you understand how changes affect the outcome.

5

Share or save your results

Use the copy or share buttons to save your results. You can also bookmark the page for quick access later.

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Frequently Asked Questions

How do I track my MPG?

Fill your tank completely, reset your trip odometer, drive normally until you refuel, fill up again and note the gallons. Divide trip miles by gallons used.

What is a good MPG?

For passenger cars, 25-35 MPG is average. 35+ is good, 40+ is excellent. Hybrids routinely achieve 45-60 MPG. SUVs average 20-28 MPG.

Why is my MPG lower in winter?

Cold weather reduces MPG by 10-20% due to denser air, winter fuel blends, longer warm-up times, and increased use of defoggers and heated seats.

Does city or highway get better MPG?

Highway driving is typically 20-30% more efficient than city driving due to fewer stops, steadier speeds, and less idling.

How does speed affect MPG?

Fuel efficiency drops above 50 mph. Each 5 mph over 50 is like paying an additional $0.25-0.50 per gallon. The sweet spot is typically 45-65 mph.