Binary File

The bytes of a text file hold 128 out of the 256 possible 8-bit patterns. Each byte is used for half of its information carrying capacity. So a text file holds about half the information that it could. A compression utility makes (nearly) maximum use of the bytes and will compress a text file to about 50% of its original size.

All files are sequences of bytes containing binary patterns (bit patterns). But people often say binary file when they mean:

Binary File (colloquial): a file in which a byte might contain any of the possible 256 patterns (in contrast to a text file in which a byte may only contain one of the 128 ASCII patterns, or fewer).

An EXE file is a binary file, as is a Word file, as is an Excel file, ... , as are all files except text files. People are often not careful, and sometimes say "binary file" when they really mean "executable file". The phrase "binary file" became common amoung MS/DOS users because DOS file utilities made a distinction between text files and all others.

Using the wrong type of file with an application can cause chaos. Don't send an executable file to a printer, or open an MS Word file with a text editor. Some applications are written to deal with several types of files. MS Word can recognize text files and files from other word processors.