How KAYAK works

We work hard as the world’s leading travel search engine to get our users the information they need so they can plan trips the way they want, confidently.

A simple search on KAYAK scans for prices on hundreds of travel sites in seconds. Whether you’re looking for flights, hotels, car hire, or more, we gather deals from across the web and put them in one place. Compare your options for the same flight, hotel or car hire and choose where you book—whether it’s directly with the airline, hotel or car agency—or even from another travel site.

Prices come straight from the travel sites to your screen, with no extra fee from KAYAK. When you’ve chosen your preferred deal, the provider of that deal simply pays us for either redirecting you to their site or helping you to book with them. This makes our service totally free for our users.

Another way we earn money is by displaying travel-related advertisements on our site. Some companies even pay us when you click on an advert that interests you.

How we list results.

There are several factors that go into how we list results after you start a search. It can be a combination of information like price and traveller ratings. For flights, we even pick up on elements that can affect your comfort, like duration and stops. But to be sure you’re finding the one you want, we have filters to help tailor your search (as well as simple sorting based on price).

Want to know more? Here’s how we sort results for different parts of the site:

Flights

Best and Recommended

Just because a deal is cheap doesn’t mean it’s necessarily the best. So by default flights are ranked to give you the best trade-off between price and convenience, based on factors such as duration, price, distance between origin and destination, number of travelers and how you started your search. The relative importance of the factors is specific to each set of search results, e.g. price will be less relevant if the cheapest flight is only slightly cheaper, but a lot longer than the quickest flight. Ultimately, it’s up to you, but saving $50 on that flight to NYC seems a lot less enticing when you realize there’s a 10-hour layover.

In case of price parity between several search results for the same flights, the ranking between these search results will be based mainly on click-through-rate and cost per click. We sometimes also judge the quality of the service you’re getting from a provider site. We’ll highlight things like a provider’s booking or baggage fees, so that when you compare your options, you’re using the total price. And if a provider isn’t upfront with their fees, making their prices less clear, we’ll tend not to recommend them.

We display deals from many different sources, including airlines, aggregators, global distribution systems, travel management companies, online travel agencies; however, our results may not always reflect all available deals.

Cheapest

Looking for the lowest price? We can make that happen. Our price sort gives you quick access to the cheapest and/or the most expensive deals—it’s your trip, so it’s up to you.

Sometimes, the same deal will be available on several provider sites. All of these providers are made visible for you to choose from, but we highlight one main provider based on factors like customer popularity or ratings. Providers can also become highlighted if they pay more for the clicks they get.

Stays (hotels and other accommodations)

We use internal algorithms to rank property results as well as sort booking option providers within a given property result. For visual simplicity, we always round up the price to the next whole number.

For property results ranking: by default, results are ranked by our 'Recommended' algorithm, which is based on a few key parameters: price, guest ratings and its popularity (measured in clicks). The relative importance of the parameters is specific to each set of search results, e.g. price will be less relevant if the price difference is very small. We also factor in the average revenue potential for KAYAK from each hotel result. In addition, you can also sort the results by price, hotel class, review score, and distance (from the destination in your search).

Sometimes, the same deal will be available on several provider sites. All of these providers are made visible for you to choose from, but we highlight one main provider based on factors such as provider’s price compared to the cheapest price and the average revenue potential for KAYAK from each hotel result. Within a hotel listing, if the cheapest offer is not displayed above the "View Deal" or "Select" button, you can see it by looking for the price highlighted in green.

Price

Looking for the lowest price? We can make that happen. Our price sort gives you quick access to the cheapest and/or the most expensive deals—it’s your trip, so it’s up to you.

Cars

Recommended

The recommended sort for car rental is mainly prioritized by price, revenue potential for KAYAK, general click popularity and the popularity of different car classes in each pickup destination (e.g. SUVs are more popular than normal at this pick-up location). For some locales (only US for now), we also factor in the review score of each rental agency. The relative importance of the factor is specific to each set of search results.

Sometimes, the same deal will be available on several provider sites. All of these providers are made visible for you to choose from, but we highlight one main provider based on factors like customer popularity or ratings. Providers can also become highlighted if they pay more for the clicks they get.

Packages

Recommended

With packages, the “Recommended” algorithm is based on a few key factors. We mainly rely on the price, the hotel’s guest rating and its popularity (measured in clicks). We also factor in the average revenue potential for KAYAK from each package result.

Within a packages listing, we order our results based on an internal algorithm that balances the prices and our revenue for the results shown. Packages shown on KAYAK are often available to book on several provider sites, each of which will pay for clicks or bookings that they get via KAYAK.

Trains and Buses

Departure time

We have sorted our train and bus results by departure time to make it easier to find an itinerary that matches your schedule.

Cheapest

Looking for the lowest price? We can make that happen. Our price sort gives you quick access to the cheapest and/or the most expensive deals—it’s your trip, so it’s up to you.

Our train and bus prices sometimes include mandatory taxes and fees, depending on locale. Check for additional fees. Some partners may charge for an additional service fee, a fee for additional baggage, or a fee for certain payment methods.

How we get prices.

We search hundreds of travel, airline, hotel and car hire sites at once to bring you options from across the web. While we always strive to have the most accurate and current information, there are occasional inaccuracies. Sometimes, it’s because the provider site isn’t updating their inventory with us or hasn’t connected to our site properly, or maybe another traveller has already booked that deal. This last scenario will sometimes happen because we cache results in order to keep site speed up (so you’re not waiting around). For example, if you and another traveller start the same search within the same minute then we’ll most likely show you both the same results. At the very least, provider sites should give us an updated inventory of prices every 24 hours. While we do search as many sites as we can, we’re still not able to search them all. There are also cases where we don’t display results from certain providers for technical or commercial reasons, or simply because we can see them having a negative effect on customer satisfaction.

How we get reviews.

Reviews appear on our site in a few ways. We show reviews and review scores from other well-known travel websites. We also show reviews from users who have made a booking through our platform while logged in or have submitted their itinerary to us (learn more about Trips here).

While we would like to publish every review, whether positive or negative, we won’t display reviews that violate our guidelines or terms of review providers, similar to our Terms of Use, including reviews that include or refer to (among other things):

  • Illegal activities;
  • Personal or sensitive information;
  • Swear words, sexual references, hate speech, discriminatory remarks, threats, etc.
  • Impersonation;
  • Is unrelated to the topic or intended use of the area of our website (in our sole discretion)
  • Spam and fake content.

And to make sure reviews are still relevant, we may stop showing reviews once they are three years old - or if there has been a change of ownership.

Our review scores are calculated by averaging the scores of reviews that we collect and reviews collected by our partners.

How we work with other companies.

KAYAK has contractual partnerships with most of the 700+ provider sites that can be seen in our results. If you’re a company that’s interested in working with us, check out our Affiliates or Hotel Owners pages.

Our company forms part of Booking Holdings Inc., which includes other travel and leisure sites such as Booking.com, Priceline.com, Agoda.com, Rentalcars.com and Opentable.com.

KAYAK also operates a portfolio of metasearch brands, including KAYAK, SWOODOO, checkfelix, momondo, Cheapflights, HotelsCombined and Mundi.

Information pursuant to Art. 11 of Regulation (EU) 2019/1150

We can provide following information on the functioning and effectiveness of our internal complaint-handling system under Regulation (EU) 2019/1150:

Total number of complaints lodged: 0
Main type of complaints: N/A
Average time to process and resolve complaints: N/A
Outcome of complaints on an aggregated basis: N/A

Last Updated: May 2022.