In computing, plain text is a term used for an ordinary "unformatted" sequential file readable as textual material without much processing.

The encoding has traditionally been either ASCII, one of its many derivatives such as ISO/IEC 646 etc., or sometimes EBCDIC. No other encodings are used in plain text files which neither contain any (character-based) structural tags such as heading marks, nor any typographic markers like bold face, italics, etc.

Unicode is today gradually replacing the older ASCII derivatives limited to 7 or 8 bit codes. It will probably serve much the same purposes, but this time permitting almost any human language as well as important punctuation and symbols such as mathematical relations (≠ ≤ ≥ ≈), multiplication (× •), etc, which are not included in the very rudimentary and incomplete ASCII set.