title: If UTF-8 is an 8-bit encoding, why does it need 1-4 bytes?
body: <p>On the Unicode site it's written that UTF-8 can be represented by 1-4 bytes. As I understand from this question <a href="https://softwareengineering.stackexchange.com/questions/77758/why-are-there-multiple-unicode-encodings">https://softwareengineering.stackexchange.com/questions/77758/why-are-there-multiple-unicode-encodings</a> UTF-8 is an 8-bits encoding. 
  So, what's the truth?
  If it's 8-bits encoding, then what's the difference between ASCII and UTF-8?
  If it's not, then why is it called UTF-8 and why do we need UTF-16 and others if they occupy the same memory?</p>