If you are an avid collector of frequent flier miles, and you really should be with the way airfares are right now, a good mileage calculator is essential. Airlines aren’t always clear about what your going to earn for a flight so I like to use MileCalc. It lets me enter my itinerary, including multi-stops, and calculates the mileage I’ll earn based on the airline I’m flying, any bonuses or promotions and my booking class. It’s particularly helpful if you are chasing elite status or trying to earn a specific number of miles for a trip you’re planning.