How to know someone has hacked my facebook account?

[Dinushan]

please tell me how we know that our facebook account is allready hacked by someone???

[Vishal]

Open your mail id that you give on the fb...
Facebook community sent a msg to ur mail which have said that u recently change ur id...

That is the only way to check out that ur id was hacked.,

[Saiko]

You Can Goto Settings>Security>Active Sessions....If you Notice any location unknown in the list then you may have been Hacked

[Ben J]

You really won't know unless someone starts posting things from your account that you obviously didn't post or if your private messages start being marked as "read" without you reading them. You will just have to watch out for suspicious activity. I would recommend changing your password frequently if you are worried about it that much. Also, never forget to logout of facebook on shared computers.

[Dolly]

unless someone knows yout password it is impossible and i mean impossible to hack a Facebook account. like there is no was somebody can acces your account without knowing your password and email

[Henok Y]

You will see odd messages and status and may be some odd friends added.

[Techie LLC]

If you suspect that your account is compromised, it's always good practice to just change your password for peace of mind.