You’ve been collecting frequent flyer miles for months or even years and now it’s time to turn them in for free travel. Before you can start cashing in your air miles, you have to know how many you have. You can find out how many air miles you have through each airline’s frequent flyer program.

Frequent Flyer Online Account

To check your air miles, visit the website of the airline and log into your online account. If you don’t have an online account, most airlines allow you to register for one for free by providing your email address. Your online account lists how many miles you currently have and provides an expiration date for those miles, if applicable. The Delta SkyMiles program, for example, list total miles, as well as miles earned on partner airlines and miles earned that go toward achieving elite status.

Customer Service

You can call the customer service department for each airline to find out how many miles you have. The customer service number is listed on the website for each airline under the “Contact Us” section. If you have a credit card co-branded for an airline, often your credit card statement will include the total number of miles you’ve earned as well as the number of miles you earned in the most recent billing period.

Point Tracking Websites

Another option for checking how many miles you have is using an online tracking program like Points.com or AwardWallet.com. These sites allow you to track a number of reward programs, providing you with the most up-to-date totals for all your frequent flyer programs in one place. You add your frequent flyer number and log-in information for each airline, and the website links all your accounts, showing you all your point totals at any given time.

Calculate Miles Earned

Several of the larger airlines, including United and Delta, have changed the way customers earn frequent flyer miles by awarding miles based on the price of the ticket, rather than the distance flown. If you want to find out how many miles you’ll earn on a certain trip, several airlines offer mileage calculators. Delta, for example, has a mileage comparison calculator on its website that tells you how many miles you’ll earn based on your elite status, price of your ticket and class of your flight. Most airlines also provide charts that explain their frequent flyer miles program and how many miles you earn for certain flights.