Will someone know if you block them on facebook

Go to a friend's chat box, Tap on the DP; Scroll down and you will find the option Block. Now, You can either block the messages or the person itself. If someone has blocked you on Facebook then you will not be able to see his/her profile nor you could see his/her personal information.

When you block messages from someone:

• When you block messages from someone:
• They'll no longer be able to contact you (ex: send you messages, call you) in Messenger or in Facebook chat.
• You'll also no longer be able to contact them in Messenger or in Facebook chat.
• If you and the person you block are in a group conversation together, you'll be notified before you enter the conversation. If you choose to enter a group conversation with the person you blocked, you'll able to see their messages and they'll be able to see yours in that conversation.

When you block messages from someone, it doesn't automatically block them on Facebook.

Blocking someone you're friends with will automatically unfriend them.

People you block won't be able to:

• See things you post on your profile
• Tag you in posts, comments or photos
• Invite you to events or groups
• Start a conversation with you
• Add you as a friend

When you block someone, you also won't be able to do things like start a conversation with them or add them as a friend. Keep in mind that blocking someone may not prevent all communications or interactions (ex: in apps or groups) and only affects your interactions with that person on Facebook.

Note: When you unblock someone, you won't automatically be friends again. If you block a friend and then unblock them, you'll need to send them a new friend request.