How can I know how long ago I killed the boss?

Question

is there a way to know the boss cooldown, other than bouncing with the door hahaha?

Answer 1

There is no official timer in game, so the usual way is to check your screenshots folder and check the time on it. Usually you can make it out from the time on whatever chat channel was open, but you can also check the name of the file or its creation date. Of course, this will only work if you have the Boss Defeated option checked on auto screenshots. 

Answer 2

Depending on what boss, you can find this information in tibia bosses. You can find the cooldown of bosses like White Pale, Rotworm Queen and creatures like Midnight Panther and Undead Cavebear. But some bosses you can know the cooldown checking the period of time they got "high chance".

But if you want to know all bosses, it's harder once you'll need to check kill statistics on tibia.com to know if the boss was killed or not.
 

Also, if you want to know a boss you killed, the best way is to select "boss defeated" on your print screen settings.