A .BMK file is usually a bookmark-like file but varies widely because `.bmk` has no universal format, so different programs embed items like labels, titles, page indices, timestamps, file paths, or coordinate data in their own way; some BMKs are plain text—readable in Notepad—while others are binary and appear as gibberish, commonly used for document bookmarks, multimedia time markers, CAD/map saved views, or app resume points, and you can usually figure out which type you have by examining where it was found and whether its text opens cleanly.

To figure out what a .BMK file is, you need to trace its folder context and then determine if it’s text or binary, so look at the directory—program-specific folders, AppData, or spots next to a PDF/video often identify the parent app—inspect Properties for info, and try opening it in Notepad: readable patterns indicate a text bookmark list, while unreadable symbols mean a binary file requiring the originating software, and similarly named neighboring files usually show what document or media the BMK belongs to.

A .BMK file varies depending on the software that created it, so determining its exact type requires discovering the generating app and examining its structure; check its storage location, the "Opens with" field, and how it looks in a text editor—if readable elements like URLs, timestamps, or structured text appear, it’s a text-based bookmark, but if it shows random symbols, it’s a binary format usable only through the program that originally produced it.

Once you know the .BMK type, how to open or convert it becomes clear, since text-based BMKs should be opened in Notepad++ to avoid accidental edits and inspected for titles, page/time markers, or references, after which you can convert them into formats like `.txt`, `.csv`, or browser bookmark lists, while binary BMKs require loading them in the program that produced them—via Import/Load/Restore features—before exporting to formats such as CSV, XML, or chapter/cue lists, and if you don’t know the source, identification through folder context and stray readable text is the most practical route.

Here's more information regarding BMK file online tool take a look at our web page. A "bookmark file" is a compact index of remembered spots telling software where to return later, usually including a label and a target like page numbers, timecodes, headings, or positional data, and when the content reopens the app restores these as bookmarks or resume points, but because the BMK only contains references and not the content itself, it becomes useless if the original file is moved, renamed, or missing.