How to upgrade with miles

These days, you’ll get the most value out of your miles by redeeming them for an upgrade. You pay for the economy seat, and then you use miles to bump up to business or first class. The difference in price between the ticket you buy and the seat you get is so huge that your money and miles go much further. Here’s a quick guide on redeeming miles for upgrades (with a few caveats thrown in).

The nuts and bolts

Mileage upgrades are almost always for one-way travel. This allows you to pick and choose which flights to upgrade; for instance, you can upgrade your red-eye outbound flight, but choose to save miles on your return day flight. Just remember that if you want to upgrade a round-trip flight, you’ll need to pay twice the number of miles listed in the award chart.

Some airlines, such as American, require you to book upgrade awards over the phone. Others, like Northwest, allow you to book a new flight and an upgrade award online in the same transaction, but request that you upgrade an existing reservation over the phone. US Airways takes a still different approach and lets you upgrade both new and existing reservations online, as long as the reservation is for a single passenger. You should always check how your preferred airline wishes upgrades to be processed before you book your tickets.

Watch out for fees

A mileage upgrade is not always a “free” upgrade. Several airlines charge a fee if you want to upgrade a discounted economy ticket to certain destinations. For instance, American charges 25,000 miles plus $250 to upgrade a discount economy ticket from North America to South America, Asia, and Europe. Continental charges between $200 and $450 to upgrade select economy fares to BusinessFirst class on international flights. These hefty fees reduce the value of your miles, and can push the price of a flight out of your price range.

Luckily, the airlines waive their usual over-the-phone booking fees for upgrades, mostly because you can’t book the upgrade online. Some airlines will assign rush fees if you book your upgrade two weeks prior to departure with no penalty. But, chances are that if you try to upgrade so close to your flight, the seats up front may have already sold out.

Know your fare class

The other important thing to know when booking mileage upgrades is your fare class. Some airlines do not allow upgrades from the most discounted economy tickets or charge fees for the service. US Airways does not allow upgrades from G-class tickets or its transatlantic “E-Savers.” And Continental bars non-elite flyers from upgrading any fare classes other than Y, H, K, N, and B on domestic flights.

Because you don’t want to book your ticket only to find out that your class of service is ineligible for an upgrade, you will want to check your airline’s rules before you book. Or, let the airlines help you with online booking options that can make this process easier. Continental, Northwest, and United allow you to search for flights that are eligible for mileage upgrades. The results indicate the price of the ticket and the miles needed for the upgrade. It’s a surefire way to avoid booking the wrong fare class; however, when we checked, upgrades weren’t always available on eligible flights.

No matter how you choose to book, remember that upper-class seats are a hot commodity these days. If you want to use your miles to snag that first- or business-class spot, you’ll want to make your reservations as early as possible.