View your reservation to see how many miles your flight covers. This is done by logging in to your frequent flier account and viewing any upcoming reservations you have. The itinerary for each flight you have reserved shows the total number of miles between your departure and destination cities, including any possible layovers you have.
Check to see how many miles you already have by viewing your frequent flier mile account with your airline. Points typically take a few days to a week to show up on your account. Don't panic if you do not see your most recent flight miles on your account. However, if you don't see the points after a few weeks, you should contact your airline.
Use a flight calculator to calculate your miles such as the one at Webflyer.com. Enter your departure and destination cities and calculate the miles between each. Depending on the number of points issued by your airline, you can then calculate the reward miles you are earning. For example: if the total distance of your flight is 500 miles and your airline issues one reward mile per mile flown, you've earned 500 frequent flier points. If your airline is offering double points for each mile flown, you simply multiply 500 miles by two points to learn you've earned 1,000 frequent flier miles.
