ffff

FFFF is a four-character sequence that is commonly encountered in computing as a hexadecimal representation. The sequence appears in contexts where hexadecimal notation is used to express numeric values or color data.

In unsigned 16-bit arithmetic, FFFF denotes 65535, the maximum value representable in 16 bits. This value is frequently seen as a boundary or sentinel in low-level code and in protocols that use 16-bit fields. In 16-bit color formats such as RGB565, 0xFFFF represents the maximum red, green, and blue components, which yields white.

In Unicode, U+FFFF is designated as a noncharacter, reserved for internal use and not assigned a visible glyph. It is not intended for plain text and should generally be avoided in data intended for interchange.

As a literal, FFFF may be written in code or documentation to indicate a full-ones pattern or to illustrate a maximum value in examples. The precise meaning of the sequence depends on the data format and context.