MPG Calculator

MPG Calculator — Estimate Fuel Costs & Consumption

Plan your road trip budget or evaluate your vehicle's fuel efficiency with this free MPG calculator. Enter your trip distance, your car's average fuel economy (miles per gallon), and the current gas price to instantly calculate how many gallons you will burn and exactly what the trip will cost you.

How fuel consumption and trip cost are calculated

Fuel economy is measured in miles per gallon (MPG) — the number of miles your vehicle can travel on one gallon of fuel. To find out how much fuel a trip requires, divide the total distance by the vehicle's MPG:

$$\text{fuel needed (gal)} = \frac{\text{distance (mi)}}{\text{fuel economy (mpg)}}$$

Once you know the fuel volume, multiply it by the price per gallon to get the total trip cost:

$$\text{trip cost (\$)} = \text{fuel needed (gal)} \times \text{fuel price (\$/gal)}$$

For example, a 300-mile trip in a car that gets 25 MPG with gas at $3.50 per gallon would require 12 gallons of fuel and cost $42.00.

What affects your vehicle's real-world MPG?

The MPG rating on your car's window sticker is a laboratory estimate. Real-world fuel economy depends on driving habits (aggressive acceleration lowers MPG), terrain (hills reduce efficiency), traffic conditions (stop-and-go city driving burns more fuel than highway cruising), vehicle maintenance (underinflated tires and dirty air filters hurt MPG), and weather (cold engines and air conditioning both increase consumption). Use this calculator with a conservative MPG estimate for a more accurate budget.

Example calculation

A 100-mile commute in a vehicle averaging 25 MPG with fuel priced at $3.50/gal:

$$\text{fuel needed} = \frac{100}{25} = 4\ \text{gallons}$$

$$\text{trip cost} = 4 \times \$3.50 = \$14.00$$

If that same trip is driven weekly, the monthly fuel cost would be about $56, and the yearly cost roughly $728. For more automotive calculators, see the Cost Per Mile Calculator, Commute Calculator, and Gas Mileage Calculator.