All about BNF Files

The BNF file type is primarily associated with BookDesigner/Nuance Dragon.

BNF	File extension: BNF
	File type:	definition file

What is a BNF file?

BNF files mostly belong to BookDesigner/Nuance Dragon. BNF files can have two main purposes. One kind holds a binary book code used in specialized desktop publishing by BookDesigner. The other kind contains language definitions written in Backus-Naur Form (BNF), a notation for describing syntax in computer languages.
Consider these details:

If your file shows a series of production rules in clear text, it is likely a grammar file for language or speech processing. In this case, a simple text editor or a tool like Nuance Dragon NaturallySpeaking may work.

If the file is binary, it probably encodes book layout instructions. Such files need the proprietary software from BookDesigner.

FilExt.com tips: This distinction is key. Check if the file opens as plain text or not. That will tell you which purpose it serves.

How can I open a BNF file?

You need a suitable software like BookDesigner/Nuance Dragon to open a BNF file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your BNF file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a BNF file directly in the browser:. Just drag the file onto this browser window and drop it.

Online BNF Text Viewer

Choose your .bnf file to view

or drag and drop it here

Online File Viewer

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How to extract texts from BNF files or capture a screenshot to PDF, JPG, DOCX, TXT, ...

1. Just click the "Choose your .bnf file to view" button on this page.
2. After your file is opened in browser,
3. click "Save as..." in the menu.
4. Then choose the file format (e.g. JPG, PDF, DOCX, TXT, ...) you want.
5. Your file will be converted and downloaded.

BNF format details:

A file format defines how the data in the file is structured. Often, the file format can be deduced from the file extension or the initial bytes (called the signature). However, different programs can use the same file extension. Furthermore, a file extension can be renamed incorrectly and double-clicking on it will then display an error when it is opened. Exact knowledge of the format is therefore important in order to solve problems occurring in files. Our evaluation of the BNF files looks like this:

The BNF file extension is not found very often and covers different formats for different programs. The two most popular formats are as follows:

• 30% of all BNF files use the same file format, which have the signature 0B 00. They consist of illegible, cryptic characters. BNF files can be up to 220 MB in size, but are often around 840 KB - 70 MB. The file type was developed only in the last few years. The keywords SS_Book_Code are typical for these files. Some examples of file names are -1_88_327.bnf. Files like these are about book, jojo, level and card.
• 9% of all BNF files start with the bytes #BNF crucial for this file format. The contents of these files are easily readable with a text editor. The file size is in the range of 120 bytes to 8 KB. Certain words are almost always found in the files, such as grammar, start, #BNF+EMV1.0 shift-jis; and #BNF+EMV2.1;. These files can be linked to grammar and wordsus.

The remaining 61% of all BNF files are files with no common format, frequently e.g. BNF and PHSD. Sometimes used for backup or email. If you want to find out which format your BNF file belongs to, just click on the button "Choose your .bnf file to view".