CTB File

What are CTB files and how to open them

Are you having problems opening a CTB file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CTB files.

What is a CTB file?

CTB files have multiple uses, and AutoCAD Color-Based Plot Style is one of them. Read more about the other uses further down the page.

AutoCAD Color-Based Plot Style

These CTB files contain the color-based plotting of objects on each layer of an AutoCAD drawing. AutoCAD is a designing software released in 1982. Each layer is used as a color plotting property, meaning if the color of the layer changes, all objects on that layer change color.

How to open CTB files

Important: Different programs may use files with the CTB file extension for different purposes, so unless you are sure which format your CTB file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different CTB openers which you will find listed below.

Last updated: September 19, 2026

All known file formats using extension .CTB

While AutoCAD Color-Based Plot Style is a popular type of CTB-file, we know of 2 different uses of the .CTB file extension. Different software may use files with the same extension for different types of data.

CherryTree Note (SQLite)

CherryTree Note (SQLite) files are the native database format used by the CherryTree note-taking application when saving documents in SQLite form. They hold all of a document's content - its hierarchical nodes, rich text, embedded images and tables, syntax highlighting, bookmarks, and metadata - in a single self-contained database. This format is best suited for larger or frequently edited documents, offering faster node access, partial updates, and more compact storage than CherryTree's full XML format. The main program writing and reading this format is CherryTree, developed by giuspen.

The SQLite storage format stores data in relational tables inside the database. Some key tables include one for nodes (titles, content, formatting, syntax highlighting), one for images (binary image data, filenames, links), one for codeboxes (code snippets with syntax, size, layout), one for tables or grids in content, one for bookmarks, and one for the tree hierarchy structure recording parent-child relationships among nodes. Document timestamps and settings such as creation time, last save time, alignment, justification, width/height constraints, tags, read-only flags and other node-level style and content metadata are stored.

The database file begins with the standard SQLite header signature SQLite format 3, indicating SQLite version 3 format. Within it there are identifiable table names and columns such as BOOKMARK, CHILDREN, NODE_ID, CODEBOX, IMAGE (with a column named png containing BLOB image data), TXT, SYNTAX, IS_RICHTXT, WIDTH, HEIGHT, and several flags and integer-typed fields for layout and enrichment. These internal identifiers help determine that a given file is this format.

Various apps that use files with this extension

These apps are known to open certain types of CTB files. Remember, different programs may use CTB files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about CTB file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.