count character and reduct credits

I am looking for some code that will count character and tell me how many they are. If they are 50 I want 1 credit if they are 100 I want 2 credit reeducated.

I already have the system behind it but I do not have this counting and deduct credit depend on how many character.

Anybody have this code on their desktop? Or can point me the right way

 

Something like this?

$credits = floor(strlen($str)/50)

PHP:

If not, can you clarify what you want.

 

Something that count character in a box. If i put 50 character including space it will take 1 credit, 100 2 credit