At a glance
- 1Google FlightsMost travellers comparing dates and routes before booking direct
- 2SkyscannerFlexible travellers looking for destination ideas
- 3KayakPeople who want a book-or-wait signal
- 4momondoA second opinion on fares found elsewhere
- 5Kiwi.comBudget travellers comfortable with self-transfer connections
How we picked
We read each site’s own help, feature and about pages on October 19, 2026 and compared the tools that save money most often: price alerts, flexible date search, searching without a fixed destination, and whether the site sells you the ticket or sends you elsewhere to book. We ranked them on how well they help a typical traveller find a lower fare and book it safely. The first four are search engines that link you to the airline or a travel agent; Kiwi.com sells the trip itself.
How to use them together
Start on Google Flights or Skyscanner with flexible dates to find the cheapest days, set price alerts on two of these tools, and check Kayak’s forecast if you are unsure whether to wait. When you find a fare, compare the same flight on the airline’s own website, add bag fees before you decide, and remember that the company you pay is the one responsible for any refund. Our guide on how to find cheap flights walks through each step, including your rights if the flight is cancelled.
No. 1, our pick
Google Flights
Best for most travellers comparing dates and routes before booking direct
The fastest way to see a whole month of fares at once, with price tracking emails and a world map for ideas, then it hands you to the airline or agent to book.
What we like
- Calendar of the lowest price for each day, plus a price graph by week or month
- Tracks routes or "Any dates" and emails you when prices change significantly
- Compares more than 300 airline and travel agency partners
- Tips flag when prices are less than usual
Keep in mind
- No dedicated app; use it in a mobile browser
- Calendar prices update about once every 24 hours, so confirm the live fare
- Price alerts
- Email tracking
- Flexible date search
- Date calendar, price graph
- Search anywhere
- Explore with world map
- Books for you
- No, links to airline or agent
- Apps
- No app, mobile web
No. 2
Skyscanner
Best for flexible travellers looking for destination ideas
The best tool for "where can I go cheaply", with Everywhere search, Whole Month dates and price alerts on the web and in its apps.
What we like
- Everywhere search lists destinations from your airport by price
- Whole Month view shows the cheapest days to fly
- Price Alerts notify you when a fare rises or falls
- Free to use; partners pay Skyscanner a commission
Keep in mind
- Whole Month prices are estimates from searches in the last eight days
- Does not compare every provider in the market, by its own account
- Price alerts
- Yes
- Flexible date search
- Whole Month
- Search anywhere
- Everywhere search
- Books for you
- No, links to airline or agent
- Apps
- iOS, Android
No. 3
Kayak
Best for people who want a book-or-wait signal
A strong all-round search with a Price Forecast that says "book now" or "wait" on routes with enough data, plus ±3 day searches and an Explore map.
What we like
- Price Forecast on routes with enough data
- Flexible dates of ±3 days and a color-coded Price Calendar
- Explore map finds destinations within your budget
- Price Alerts by email
Keep in mind
- Does not sell tickets, so changes go through the airline or agent you book with
- Price Forecast only appears when Kayak has enough data
- Price alerts
- Email alerts
- Flexible date search
- ±3 days, Price Calendar
- Search anywhere
- Explore map
- Books for you
- No, links to airline or agent
- Apps
- iOS, Android
No. 4
momondo
Best for a second opinion on fares found elsewhere
A clean search site managed by Kayak, with price alerts, an Explore map and a Price Calendar on popular routes, worth running alongside the others.
What we like
- Price Alerts on your favorite routes, on the web or in the app
- Explore map finds trips within your budget
- Says it never adds booking fees
Keep in mind
- Price Calendar only on its most popular routes
- Managed by Kayak, so expect overlap with Kayak's results
- Price alerts
- Yes
- Flexible date search
- Price Calendar (popular routes)
- Search anywhere
- Explore map
- Books for you
- No, links to airline or agent
- Apps
- iOS, Android
No. 5
Kiwi.com
Best for budget travellers comfortable with self-transfer connections
The only one of the five that books the trip itself, often by combining separate airlines into self-transfer routes, which can be cheaper but carries more risk.
What we like
- Books the trip itself and provides customer support and post-booking services
- Search to Anywhere and Nomad for multi-city trips
- Price alerts and an interactive calendar of cheap dates
- Filters by number of bags
Keep in mind
- On self-transfer routes, airlines are not obliged to rebook you if you miss the next flight
- Disruption Protection is part of the Kiwi.com Guarantee, which you add to a booking
- Price alerts
- Yes
- Flexible date search
- Interactive calendar
- Search anywhere
- Search to Anywhere
- Books for you
- Yes
- Apps
- iOS, Android
Compare all five
| Our pickGoogle Flights | No. 2Skyscanner | No. 3Kayak | No. 4momondo | No. 5Kiwi.com | |
|---|---|---|---|---|---|
| Price alerts | Email tracking | Yes | Email alerts | Yes | Yes |
| Flexible date search | Date calendar, price graph | Whole Month | ±3 days, Price Calendar | Price Calendar (popular routes) | Interactive calendar |
| Search anywhere | Explore with world map | Everywhere search | Explore map | Explore map | Search to Anywhere |
| Books for you | No, links to airline or agent | No, links to airline or agent | No, links to airline or agent | No, links to airline or agent | Yes |
| Apps | No app, mobile web | iOS, Android | iOS, Android | iOS, Android | iOS, Android |
