How do I count Facebook messages?

If you mean counting the messages in a conversation, then you could do so by clicking on "See full conversation" and scroll up, the number of messages in the conversation will be visible. 

On the other hand, if you wish to know the total number of conversations (chats) or people from whom you have received messages, just click on the messages icon and you will be able to see the number of chats in your "inbox" as well as those in your "others" folder.  

Hope that was helpful.

If you are using Chrome, try an extension named

Messenger Counter

offered by Alexander Nørup

Just install it and count your messages. I'd strongly suggest you delete this extension once used in order to avoid your data being stolen.
This is easy to use. I don't know about other browsers.

There used to be a facebook app to count messages. But that doesn't work now.

There is one other method by scrolling up your chat (The middle column), but this method is not workable.

If you are a techie and want to be little creative just try hands on some script which will ease this out for you, this is the era of scripting and automation, just give it a try :)

(Works on Mac, there probably is a way for Windows) If you want an exact number and the distribution of times/dates, you can archive your fb message data.  The messages are enclosed in 
 tags, so you can use a macro to remove them (I use Emacs). Then you have a htm file that you can open in Textedit and convert to .txt, but with the formatting of the html.  After that you can just delete the conversations that do not interest you you and count the lines.

This probably isn't worth your time to figure out, but being able to look at the data is interesting.

This probably isn't worth your time to figure out, but being able to look at the data is interesting. Just go to the message box. Open the one's message you would like to countand then scroll it to view oldmessages you will see at top a number indicating of messageschats you have done

Just go to the message box. Open the one's message you would like to count and then scroll it to 

view old messages you will see at top a number indicating of messages chats you have done.

Open the one's message you would like to count and then scroll it to view old messages you will see at top a number indicating of messages chats you have done.

Probably you want to know about number of messages not chats.

You can do by yourself too.

Tap on message icon there will no of conversation and in each conversations when you open there will be no of remaining messages in that conversation.

Then do some little math work and calcualte all information.

And also use this application Messenger Counter.

Hope it works for you!

Good Luck :) 

First go to primary school learn counting than count your all the messages the last number which your message get is the total number of messages you have....

You can count your facebook messages. You has to do it manually. Counting one by one. If you ask the question how many messages do i have.Facebook replies Are you interested ib friends or numbers. Got it.

For that go on to message list and there is one other method by scrolling up your chat (The middle column), but this method is not workable.

If you are using Chrome, try an extension named

Messenger Counter

offered by Alexander Nørup

Just install it and count your messages.