.txt File Extension

What kind of file is a .txt?

A .txt file normally contains plain text: characters and line breaks without required fonts, images, page layout, or formatting commands. Its standard media type is text/plain. The suffix is a convention rather than proof of the content, and plain text has no fixed magic bytes.¹

Character encoding matters. ASCII is limited, while UTF-8 can represent the full Unicode repertoire and is the safest modern choice for sharing text. A file may also begin with a byte order mark, but many UTF-8 files do not. Software therefore relies on declared metadata, the filename, and cautious content detection rather than a universal signature.

How do I open a .txt on my computer?

TXT files work on virtually every current platform:

• On Windows, use Notepad, Visual Studio Code, or another text editor.
• On macOS, use TextEdit in plain-text mode, a code editor, or Terminal tools.
• On Linux, use the desktop text editor, Vim, Emacs, Nano, or a code editor.
• On iPhone, iPad, and Android, use a files app or text-editing app.

If accented letters, emoji, or non-Latin writing looks garbled, reopen the file using its original encoding before saving it as UTF-8. Also watch line endings. Local Unix-like files commonly use LF, while Windows files often use CRLF. Most modern editors accept both, but scripts and version-control diffs may treat them differently.²

Poly support for .txt

Poly opens readable TXT files in a code-friendly editor, indexes their content for exact and semantic search, and makes the text available to the Poly agent. Search results can focus on the relevant text range, which is useful for notes, logs, transcripts, and exported records.

UTF-8 gives the most reliable results. A legacy encoding or binary file disguised with a .txt suffix may display incorrectly or remain unavailable for content-aware search.

History of .txt

The suffix grew from the simple practice of labeling files that held text rather than a specialized binary format. MIME formally introduced text/plain in RFC 1341 in June 1992, and RFC 2046 replaced that definition in 1996.³

In 2008, RFC 5147 documented .txt as the commonly used filename extension for plain text and standardized URI fragments for addressing character and line ranges.¹ The format stayed useful because it depends on very little, but encoding and newline conventions still have to be agreed upon.

Working with .txt and alternatives

Choose a format based on the structure you need:

Converting a rich document to TXT discards styling, tables, images, tracked changes, and page layout. Apple specifically notes that changing a rich-text document to plain text removes its styles and saves the result as .txt.⁴ Keep the original when you may need that information later.

Plain text is not automatically harmless. It can contain terminal escape sequences, misleading bidirectional Unicode controls, secrets, or instructions that another tool interprets. Inspect an unfamiliar file in a modern editor before printing it to a terminal or passing it to a command.¹