If you've ever priced one-way international flights, you probably found that two one-way flights are more expensive than a round-trip flight. However, this isn't always the case — especially when booking flights using points and miles. On many trips, loyalty programs charge one-way award flights at half of the round-trip award price.

But there are other considerations besides just price when comparing round-trip versus one-way flights. Travelers might be surprised to find that booking a round-trip award flight could lead to issues if you have a change in plans mid-trip.

Here's a look at factors to consider when booking round-trip versus one-way flights and answers to some frequently asked questions.

Round-trip vs. one-way flights when booking revenue fares

When booking paid flights, our advice is pretty simple: book the option that's cheapest for your trip. If a round-trip flight is cheaper than two one-way flights, there's no reason to book two one-way flights.

If two one-way flights are the same price as a round-trip, it will generally make sense to book the round-trip flight. After all, now that many airlines have eliminated change fees, it's possible to change — or even cancel — the return portion of the round trip.

For example, while in Europe in the middle of a round-trip Delta flight, my mother had to rush back to the U.S. to deal with a family emergency. Delta would allow changes to her flight with no change fees. However, as last-minute flights were nearly sold out, the price difference to change her Delta flights was too pricey. Instead, we opted to book an American Airlines award to get her home.

Delta canceled the return portion of her round-trip flight and provided a travel credit toward future travel, so booking a round-trip flight instead of two one-way flights didn't limit her options.

Round-trip vs. one-way flights when using miles

When using points and miles to book award flights, you have a different set of factors to consider. In the case of award travel, it can make sense to book two one-way flights instead of a round-trip award.

More flexibility when booking two one-way awards

If the price is the same, consider booking two one-way awards to gain extra flexibility. Most U.S. airlines have dropped change fees on both award and paid flights. However, you won't be able to change some awards after taking the first leg of the flight.

For example, American Airlines AAdvantage Web Special awards aren't changeable. American Airlines lets travelers cancel Web Special awards and reinstate miles before departure. However, once you start your trip, these awards can't be changed or canceled. If your plans change, you won't be able to get a refund for the remaining flights.

Other airlines aren't as punitive. For example, if you cancel a United award flight mid-trip, you'll retain the miles as a future flight credit. While the miles won't be refunded to your account, at least you'll have the chance to use them in the future.

Watch for higher taxes and fees when booking two one-way awards

When considering whether to book round-trip versus one-way awards, it's important to price out both options — particularly when flying overseas. Some airlines charge higher taxes and fees for awards that originate in certain regions of the world.

Delta SkyMiles is infamous for charging higher fees for award flights that originate in Europe. Also, particularly for international flights, Delta will often price round-trip award flights at less than the cost of two one-way awards.

For example, take a round-trip award from New York to Paris. Delta charges 50,000 SkyMiles plus $85 in taxes and fees for a round-trip main cabin award.

However, if you book the same flights as two one-way awards, you'll pay a total of 74,000 SkyMiles plus roughly $220 in taxes and fees. The outbound award costs 37,000 miles plus $6 in taxes and fees. Then, you'll need to pay another 37,000 SkyMiles plus around $220 to fly home.

In a situation like this, it makes sense to book a round-trip award. You'll save on miles and out-of-pocket costs.

Consider change fees on award flights

Most U.S. airlines have eliminated change fees on both paid flights and award tickets. However, that's not the case with all mileage programs. If you're booking through a mileage program that charges change fees, you may want to book a round-trip award to reduce the fees you could pay if you need to cancel the trip.

Consider alternatives to booking two one-way flights

Say you're considering flying to Europe to take a cruise from Budapest to Munich. One might assume that your only options are to:

Book a round-trip flight into one of the cities plus book a one-way intra-Europe flight between them.

Book two one-way flights — one-way into Budapest and one-way back from Munich.

However, there's a third option: booking an "open-jaw" flight. Many airlines will let you book a flight into Budapest and a flight back from Munich on the same ticket. Rather than pricing these flights as two one-way flights, the airline generally prices the flights similar to a round-trip.

If you're using airline miles to book these flights, check to see if it's cheaper to book two one-way awards or an open-jaw award. As outlined in the Delta example above, award flights originating in Europe can have much higher taxes and fees. So it might make sense to book the two award segments together as a multi-city award.

Frequently asked questionsAre two one-way flights more expensive than a round-trip?

In the past, airlines charged more for booking two one-way flights rather than a round-trip on the same route. However, this isn't the case anymore on most domestic flights and even some international flights — mostly thanks to competition from low-cost carriers.

Why are one-way flights more expensive?

In short, airlines charge more for one-way flights on the routes when they can get away with doing so. If only one airline is operating a particular route, it might increase the price of one-way flights to generate more revenue from business travelers and others that are willing to pay more for the nonstop flight.

However, when there's competition from other airlines, the cost of one-way flights often drops to compete with the other airlines serving that route.

Are round-trip flights cheaper?

Booking a round-trip flight can be cheaper than booking one-way tickets on the same flights. Before booking two one-way flights, check the round-trip price to see if it's cheaper. Even if you're flying out of a different city than you're flying into, booking a so-called "open-jaw" flight could be much cheaper than booking two one-way flights.

Is it cheaper to fly one way or round trip when using points and miles?

Most U.S. airline loyalty programs will charge the same number of miles whether you book round-trip or two one-way flights. Because of this, it can make sense to book two one-way flights instead of a round-trip award to get flexibility in case you need to change or cancel plans.

However, this isn't always the case. Some loyalty programs — such as Delta — charge fewer miles for booking a round-trip award instead of two one-way flights. We recommend pricing out award flights both ways just to be sure.

Are two one-way flights more expensive than a round-trip?

In the past, airlines charged more for booking two one-way flights rather than a round-trip on the same route. However, this isn't the case anymore on most domestic flights and even some international flights — mostly thanks to competition from low-cost carriers.

Why are one-way flights more expensive?

In short, airlines charge more for one-way flights on the routes when they can get away with doing so. If only one airline is operating a particular route, it might increase the price of one-way flights to generate more revenue from business travelers and others that are willing to pay more for the nonstop flight.

However, when there's competition from other airlines, the cost of one-way flights often drops to compete with the other airlines serving that route.

Are round-trip flights cheaper?

Booking a round-trip flight can be cheaper than booking one-way tickets on the same flights. Before booking two one-way flights, check the round-trip price to see if it's cheaper. Even if you're flying out of a different city than you're flying into, booking a so-called "open-jaw" flight could be much cheaper than booking two one-way flights.

Is it cheaper to fly one way or round trip when using points and miles?

Most U.S.

airline loyalty programs

will charge the same number of miles whether you book round-trip or two one-way flights. Because of this, it can make sense to book two one-way flights instead of a round-trip award to get flexibility in case you need to change or cancel plans.

However, this isn't always the case. Some loyalty programs — such as Delta — charge fewer miles for booking a round-trip award instead of two one-way flights. We recommend pricing out award flights both ways just to be sure.