Gas Mileage & Fuel Economy MPG Calculator

Gas mileage (MPG) measures vehicle fuel economy efficiency. Higher MPG reduces daily fuel expenses and lowers lifetime vehicle operating costs.

To use the Gas Mileage & Fuel Economy MPG Calculator, enter your Trip Miles Driven, Gas Gallons Consumed, Gas Price per Gallon. The calculator instantly computes Calculated Gas Mileage (MPG), Fuel Cost per Mile and more. Results update in real time as you change any input — no submit button needed.

How to Use This Calculator

Enter your Trip Miles Driven (e.g. 300 in miles), Gas Gallons Consumed (e.g. 10.0 in gallons), and Gas Price per Gallon (e.g. 3.50 in /gal). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Gas Mileage MPG = Trip Miles Driven ÷ Gas Gallons Consumed

Fuel Cost per Mile (/mi) = Gas Price per Gallon ÷ Calculated MPG

Annual Gas Expense (/yr) = Fuel Cost per Mile × 12,000 miles/yr

Worked Example

300 miles driven using 10.0 gallons of gas at 3.50/gallon:

Calculated MPG = 300 / 10.0 = 30.0 MPG.

Fuel Cost per Mile = 3.50 / 30.0 = 0.117 per mile (1,400.00 annual gas expense for 12,000 miles).

Understanding Your Result

Age calculations depend on the calendar system and jurisdiction. Legal age of majority varies: 18 in most US states, 19 in Alabama and Nebraska, 21 historically for alcohol purchase. Many insurance products, loan terms, and benefit programs use age as of the last birthday (age nearest birthday in some actuarial contexts). Retirement age calculations: full Social Security benefit at age 67 (born 1960+); early benefit at 62 with 25–30% permanent reduction; delayed credits add 8% per year up to age 70.