Visit the website of the airline with which you have frequent-flier miles. Do a Web search for the airline if you do not know the exact URL for the site.
Locate the frequent-flier program on the airline site. Most airline websites provide a link to the frequent-flier program along the top of the page. The exact name of the frequent-flier program differs by airline (Delta SkyMiles, United Mileage Plus, American AAdvantage), but the link should mention airline miles or flight rewards.
Log in to your frequent-flier account or create a new account using your frequent-flier information. When you signed up to receive frequent-flier miles, the airline will have given you a number or card with your account information. Your account number should also appear on any mailings or emails you receive from the airline. If you cannot locate your account or log-in information, contact the airline's customer service by phone or email. A link to the contact information should be at the bottom of the website.
Look at the main page of your frequent-flier account page. The number of miles you have and the expiration date for using the miles should be clearly displayed.
