Ticket prices go up and down all the time, depending on many different factors that are specific to a particular flight or route. Those things can include:

How booked up the flight is. If it isn’t selling well, the airline might be tempted to sell off more seats at lower prices, so they can fill up the plane. They’ll save the high fares for last-minute buyers, as those people probably really need to be on that flight, no matter the price — and those high fares help the airline cover the costs of the journey.

Real-time bookings and cancellations. These days, airlines use complex computer software and algorithms to adjust their prices, so they can respond to supply and demand in real time. For example, if some bookings get cancelled close to the flight date, the software might automatically offer those seats at a very low price to make sure they get filled. That’s why you’ll see prices constantly dipping and climbing as you search for the perfect fare.

Whether the route is typically used by business or leisure travellers. If it’s a route that’s used a lot by business travellers, airlines might start by selling tickets at lower prices to tempt leisure travellers (so they can fill up the plane). They may then raise prices as the flight date nears, because business travellers usually book at the last minute (and on their corporate credit card).

Of course, this depends on a number of different and ever-changing factors, like how well that particular flight or route is selling at any given time. In general though, airlines offer cheaper prices when flights are first released, so booking earlier could help you to find a cheaper deal.

Luckily, we’ve done some of the number crunching for you. Use our tool above to discover how many weeks before your preferred departure date you are likely to find the cheapest flights.

Or if you’re flexible on when you fly, use Skyscanner’s ‘Whole Month’ search to find the cheapest day to travel to your chosen destination.

Tuesday is often believed to be a cheaper day to book flights because airlines often release sales starting from Monday night or Tuesday morning. This means that if you happen to look at flights on a Tuesday after a sale starts, you will probably get better flight deals than you would if searching on a Saturday.Ultimately though, finding a cheap flight is less about the day you book, and more about how popular your flight is since flights are priced based on supply and demand.

This varies significantly depending on the destination. But if you already know where you want to go, Cheapest Month search will show you the cheapest month of the year to visit. Just select ‘flexible dates’ in the search window after entering your destination. After you’ve selected the cheapest month, you’ll then be able to see the cheapest day to fly in your chosen month.