字节（（英语：Byte），通常用作计算机信息计量单位，不分数据类型。一个字节代表八个比特（（英语：Bit）。它也是进程设计语言里不可缺少的基本数据类型——整数。

字节是现代计算机中连续的、固定数量的比特（二进制），即八个比特为一字节。

八个二进位经常在规范中被称为Octet（八位组），例如在一些工业标准、网络及电信技术里。

Byte（字节）可被缩写成B，例如MB表示Megabyte；Bit（比特）可被缩写成b（小写），例如Mb表示Megabit。

法语国家有时把「o」用于「octet」。很多人不接受，因为这在国际单位制中有与零混淆的风险。

The byte (/ˈbaɪt/) is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. The size of the byte has historically been hardware dependent and no definitive standards existed that mandated the size. The de facto standard of eight bits is a convenient power of two permitting the values 0 through 255 for one byte. The international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits and processor designers optimize for this common usage. The popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit size.