How to turn your airline miles into a great vacation

There are over a dozen websites that show award redemption rates across airlines. Customers have taken note of these so-called award-search sites: Point.me, to take one example, reached one million monthly users in November. Other sites include PointsYeah, Pointhound, AwardTool and SeatSpy.

“People are earning all these points and miles from all these credit cards, and they want to use them effectively," says Greg Davis-Kean, founder of travel website Frequent Miler.

Here’s what you need to know before using these services.

How do award-search websites work?

At their core, these sites function much like travel sites such as Kayak and Expedia. To search for a flight, users enter their departure and destination airports and the dates of their travel. But instead of showing how much a flight costs in cash, these sites present prices in points or miles.

Many of these sites include features that allow for more open-ended searches if you don’t have a time frame or destination in mind. Some allow you to search for hotels, too.

The sites vary in many ways, including which airlines are factored into search results. For instance, Point.me lets you search for round-trip tickets, while Roame.travel looks for one-way fares. Some sites enable users to set up price alerts or seek out concierge services for an additional charge.

How much does it cost?

Unlike sites like Kayak or Expedia, most award-search services require a paid subscription to get access to the full array of tools they offer. Some features of Point.me are available for free to American Express and Bilt customers, but you have to subscribe to use tools such as advanced filters or alerts. Point.me offers a standard subscription for $129 a year and a premium subscription for $260 a year.

On Seats.aero, users can search for flights up to 60 days out for free, but to access a full year’s worth of award inventory they must pay either $10 a month or $100 a year.

Points Path is another award-search service, which works as a browser extension to populate award-redemption rates when travelers explore travel options using Google Flights. It offers results for a wider array of frequent-flier programs to paid users.

Can you book a trip directly?

No. Once a traveler identifies a flight they wish to book, they must then go to the airline’s website directly to do so.

“You still need to do work to make the most of these tools," says Kyle Potter, executive editor of travel website and subscription service Thrifty Traveler.

That’s where trouble can arise, points-and-miles veterans warn. Some sites produce search results using cached data. Depending on the award-search tool a person is using, results might not be current. Users should verify pricing shown on these sites is accurate on the airline’s own website.

Even then, it’s not always a seamless process. In the time it takes for miles or points to transfer over, a flight could sell out or the pricing could change. Most of the time it’s not possible to transfer points back to a credit card.

How do award-search websites find booking options and prices?

Most of these services, including Points Path and Seats.aero, scrape airline websites for pricing information. Sometimes this means having bots regularly pull pricing, while other sites only scrape the airline systems in response to specific user searches.

Point.me says it uses direct software connections to the systems powering airlines’ frequent-flier programs. So when a user identifies pricing for an Air France flight, for instance, that figure was pulled directly from the airline’s internal system, says Tiffany Funk, Point.me’s co-founder. This aims to prevent cases of “phantom availability," where an airline’s website displays a supposed award seat that isn’t actually bookable.

The Wall Street Journal put these tools to the test by performing the same flight search across seven of these websites. For an early May flight between Atlanta and Paris, quotes ranged from 9,500 points plus over $200 in taxes and fees via Roame to nearly 40,000 miles plus $6 in taxes and fees via Points Path. Three sites—Point.me, PointsYeah and AwardTool—featured the same top result, an Air France flight that cost 25,000 points plus $98 in taxes and fees.

Which site is right for me?

Some sites are better suited for beginners. Point.me, for instance, flags which credit-card programs a traveler can transfer points from to book a flight with a certain airline and provides other booking tips. With some others, such as Seats.aero, having a working knowledge of airport codes and airline transfer partners can help the user get the most mileage out of these tools.

Write to Jacob Passy at jacob.passy@wsj.com