4 octets of UTF-8 suffice to cover all Unicode characters. Unicode is essentially 21-bit (U+0 to U+10FFFF), not 32-bit. The BMP is 16 bits, U+0 to U+FFFF. 3

4 octets of UTF-8 suffice to cover all Unicode characters. Unicode is essentially 21-bit (U+0 to U+10FFFF), not 32-bit. The BMP is 16 bits, U+0 to U+FFFF. 3 octets suffice for it. It's useful to know that MySQL support outside the BMP doesn't work, but I would guess it's a generic problem affecting all Unicode support, not restricted to UTF-8. (Yes, UTF-8 was defined to go up to 6 octets and cover 31 bits. As used with Unicode, only up to 4 are supposed to be used...)