Plain text contains only characters and letters with no formatting, while rich text allows formatting like bold, italics, colors, and fonts. Plain text files are smaller and work on any device, but rich text files can include styled text, images, and special formatting.
What is Plain Text
Plain text is the simplest form of digital text that contains only basic characters, numbers, and punctuation marks. It has no formatting information like fonts, colors, bold, or italics stored within the file. When you open a plain text file, you see exactly what was typed with no special styling or appearance changes. Plain text files are universal and can be opened on computers, phones, tablets, and even very old devices.
What is Rich Text
Rich text is formatted text that includes styling and design elements beyond basic characters. Rich text files can contain bold and italic text, different fonts, colors, sizes, images, tables, and other visual formatting. The file stores special codes behind the scenes that tell the program how to display each part of the text. Examples include Microsoft Word documents and PDFs that look nicely formatted when opened.
File Size Differences
Plain text files are very small because they only store the letters, numbers, and symbols you type. Rich text files are larger because they contain additional code that describes all the formatting, colors, fonts, and images included in the document. A plain text file with 1,000 words might be 5 kilobytes, while the same text as a rich text document could be 50 kilobytes or larger.
Compatibility and Accessibility
Plain text files work on virtually every device and program that exists, from old computers to modern smartphones. Rich text files require specific software to open and display correctly. If you open a rich text file with the wrong program, the formatting may not show up properly or appear as strange symbols. This makes plain text more reliable for sharing across different platforms and devices.
Common Use Cases
Plain text is used for simple notes, coding programs, log files, and any situation where you only need basic text without styling. Rich text is used for professional documents, reports, letters, newsletters, and any material where appearance and formatting matter. Writers often use rich text formats like DOCX for documents, while programmers use plain text for code files. 
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