Type Approx. Length Exact Max. Length Allowed
TINYTEXT 256 Bytes 255 characters
TEXT 64 Kilobytes 65,535 characters
MEDIUMTEXT 16 Megabytes 16,777,215 characters
LONGTEXT 4 Gigabytes 4,294,967,295 characters
Basically, it's like:
"Exact Max. Length Allowed" = "Approx. Length" in bytes - 1
Note: If using multibyte characters (like Arabic, where each
Arabic character takes 2 bytes), the column "Exact Max.
Length Allowed" for TINYTEXT can hold be up to 127
Arabic characters (Note: space, dash, underscore,
and other such characters, are 1-byte characters).