Question: 1 letter how many bit?
Answer: It depends what is the character and what encoding it is in: An ASCII character in 8-bit ASCII encoding is 8 bits (1 byte), though it can fit in 7 bits. An ISO-8895-1 character in ISO-8859-1 encoding is 8 bits (1 byte). A Unicode character in UTF-8 encoding is between 8 bits (1 byte) and 32 bits (4 bytes).