Compare Cheap Flights: Google Flights, Kayak and Price Alerts Side by Side
Which tool should you use to compare cheap flights? A side-by-side look at Google Flights, Kayak and a deal alert service, and when each one fits.
To compare cheap flights, use a search tool when you know your route and dates, and a deal alert when you are flexible and want to be told about a low fare. Most travellers end up using both. Here is how they differ and when each one wins.
This is not a ranking. The tools do different jobs, so the useful question is which job you have today.
The three options
- Google Flights is a flight search tool. Its help pages describe a date grid, a price graph, a way to explore destinations on a map, and price tracking with email alerts.
- Kayak is a comparison site. Its help center lists price alerts and a "booking and checkout" section, and a commenter in r/Flights describes it as a search engine that sends you on to the airline or a travel agency to buy.
- Cheap Flights Alert is a free service that watches flight prices from the departure airport you choose and messages you when a fare is clearly cheaper than usual. It does not sell or book tickets.
Other comparison sites exist and work in a similar way. The same logic applies to them.
Side by side
| Google Flights | Kayak | Cheap Flights Alert | |
|---|---|---|---|
| Best for | A known route, comparing dates | Comparing many providers for one trip | Flexible travellers who want to hear about deals |
| You start with | A route and dates, or a region | A route and dates | Your home airport |
| Flexible-date tools | Date grid, price graph, explore map | Check on its site | You do not enter dates; deals arrive with their dates |
| Price alerts | Yes, for a route or flight, by email | Yes, price alerts | Yes, by WhatsApp, Telegram or email, only for clearly cheap fares |
| Books the ticket | No, it sends you on to book | You book through a provider | No, it sends a link to book |
| Cost to you | Free | Free | Free |
When Google Flights fits
Choose it when you have a destination and want to see the lowest price across days. According to Google's help page, the calendar shows the lowest total price for each day and updates about once every 24 hours, and the price graph shows trends by month or week. If you do not know where to go, it lets you browse destinations on a map.
It can also track prices. Per the tracking help page, you can track a route or a specific flight, and with "Any dates" you are emailed when the route's minimum price drops significantly over a month.
Limits: you must start the search yourself and choose a route. It is a tool you go to, not one that comes to you.
When Kayak fits
Choose a comparison site when you want to see the same trip offered by several sellers. It has a help center with price alerts and a booking section, and it lets you report a price that does not match.
The honest caveat is booking. In a thread in r/travel, someone asking whether aggregators are getting harder to use said the price changed or the booking was refused after redirecting to a provider. A commenter there suggested that aggregators can show out-of-date data, which is a good reason to check the final price at checkout. Another thread, on airline website versus Kayak, has many commenters saying they search on a comparison site but book directly with the airline, because changes and cancellations are easier to handle that way. That is a preference, not a rule, but it is worth thinking about before you pay a third party.
When a deal alert fits
Choose Cheap Flights Alert when you can go to several places and want a nudge when something is cheap. Each fare is compared with recent prices seen from the same airport, and only a deal score of 80% or more is sent. You get one message per deal, with the price, the travel dates and a link to book.
Limits to know:
- It covers major airports in the United States and Europe, and you pick one home airport. You can see an airport's current lowest fares on its page, for example London Heathrow or Atlanta.
- It does not guarantee that a fare will still be available when you click. The final price is the one on the booking site.
- It does not predict whether prices will rise, and it does not offer hotels, cars or packages.
- If you must fly on exact dates, you will do better with a search tool.
A simple workflow that uses all three
- Find the deal. Let an alert tell you when a fare from your airport is clearly low.
- Check it. Open Google Flights and compare the dates around the deal to see whether a day earlier or later is cheaper.
- Confirm the price. Compare a second site if you like, then check the total with bags on the page where you will actually pay.
- Book once. Book all passengers together, and read the change and cancellation rules first.
If you are still working out your approach, how to find cheap flights, step by step lays out a method that works with any of these tools. If the airline type matters to your decision, read low-cost vs full-service airlines.
What to remember
- A search tool answers "what is the price for this trip?" An alert answers "when is a price clearly low?"
- Booking directly with the airline can make changes easier, but compare for yourself.
- Always check the final price with bags before you pay.
Sources
Frequently asked questions
- What is the best site to compare cheap flights?
- It depends on the job. Google Flights is strong for a known route and flexible dates, a comparison site like Kayak shows several sellers, and a deal alert tells you when a fare from your airport is clearly cheap.
- Is Cheap Flights Alert a replacement for Google Flights?
- No. They do different things. Use Google Flights to search a specific route and dates, and Cheap Flights Alert to hear about clearly cheap fares from your home airport.
- Should I book through a comparison site or the airline?
- Comparing on a search site is fine, but many travellers book with the airline because changes and refunds are then handled by one company. Check the final price on the page where you pay.
- How does Cheap Flights Alert decide that a fare is a deal?
- It compares each fare with recent prices from the same airport. The deal score shows how much better than usual the fare is, and only deals scoring 80% or more are sent.
- Do these tools cost anything?
- Google Flights and Kayak are free to search, and Cheap Flights Alert is free. If you book through a partner link, Cheap Flights Alert may earn a commission at no extra cost to you.
Your next trip could cost far less
Why pay more? Join free and let the deals come to you.
Join for free