Octet Draw

Free, open-source chemical drawing for Mac, Windows and Linux. It opens and saves ChemDraw files, and it works with no internet connection.

Octet Draw is part of Octet, the Open source Chemistry Toolkit for Experiments & Typesetting. Made by Sam Ellis, with Claude.

Download

Get the latest version from octet.software or the Releases page.

Computer	File
Mac	Octet-Draw-mac.dmg (Apple silicon and Intel)
Windows	Octet-Draw-windows.exe. For a PC with no internet: Octet.Draw_<version>_x64-offline-setup.exe
Linux	.deb (Ubuntu, Debian), .rpm (Fedora) or Octet-Draw-linux.AppImage

To uninstall: on a Mac, drag Octet Draw from Applications to the Bin. On Windows, Settings > Apps > Installed apps > Octet Draw > Uninstall. On Linux, remove the package with your package manager, or delete the AppImage.

System requirements

• macOS 12 Monterey or later, on Apple silicon or Intel.
• Windows 10 or 11, 64-bit.
• Linux, 64-bit, with WebKitGTK 4.1 (for example Ubuntu 22.04 or Debian 12, or later).

Octet needs no account and no internet connection.

What it does

• Draws structures, reactions, arrows, shapes and text, with ChemDraw's keyboard shortcuts.
• Starts each drawing in the ACS Document 1996 style. Settings has other journal styles.
• Opens and saves ChemDraw files (CDXML and CDX). Imports and exports MOL, SDF, SMILES and InChI.
• Saves .oct files by default: CDXML with Octet's own drawing in it. ChemDraw opens a .oct file as an empty document. For ChemDraw users, save a .cdxml, or set Settings > Import and export > Save new drawings as to ChemDraw XML (.cdxml). A file saved again in ChemDraw keeps the structures but not Octet's own extras.
• Exports PDF, SVG and PNG. On the Mac, Copy puts the drawing into Word, PowerPoint and Keynote, and it pastes back into Octet or ChemDraw as a structure.
• Turns names into structures and structures into names, offline.
• Predicts ¹H and ¹³C NMR shifts, and shows formula, mass and other properties.

Community

Ask a question, suggest an idea or show what you drew in Discussions.

Report a problem

Use Help > Report a Problem in Octet, or open an issue. For a security problem, follow SECURITY.md instead.

Run from source

You need Node.js 24 and Rust.

npm install
npm run tauri dev

npm test runs the type check and every check file. docs/release.md tells how releases are built and signed.

Sam

Hello everyone. I'm a student in the Nitschke group at the University of Cambridge. Before that, I was an undergraduate at the University of Manchester.

Chemistry is fantastic, but communicating it is extremely difficult. This is my first attempt to make it ever-so-slightly easier.

Always up for a chat about my research, this project, or anything else.

Thanks to my wonderful pals for beta testing: Elliot Thaw, Dylan Davies-Jones, James Baron, Elena Lahr, Seb Kinzie and Ying Hou.

Email sam[at]octet.software, or for chemistry, spe29[at]cam.ac.uk. You can also find me on LinkedIn.

Privacy

Octet works with no network: no account, no licence check, no analytics, no crash reporting. It goes online only in these cases:

• Update check. When it opens, Octet asks GitHub whether a newer version exists. It sends no drawings, files or personal details. Turn it off in Settings > General > Updates. See decision 0010.
• Search Reaxys opens Reaxys (Elsevier) in your browser with the selected structure in the address, only when you press it.
• Search PubChem opens PubChem (the US National Library of Medicine) in your browser with the selected structure in the address, only when you press it.

The structure stays in your browser's history. To hide both searches, turn off Settings > Import and export > Online search. See decision 0008.

Code signing policy

GitHub Actions builds every installer from this repository. Nothing is built or signed on a personal computer.

• Mac: signed with an Apple Developer ID and notarised by Apple.

• Windows: signing is being set up. Until then, Windows may warn you the first time you open the installer: click More info, then Run anyway.

• Committers and reviewers: Sam Ellis (SamChemMan)

• Approvers: Sam Ellis (SamChemMan)

The policy is also at octet.software/code-signing.

Licence

Octet is free and open-source software under the Apache License 2.0.

Copyright © 2026 Sam Ellis. Made in Manchester and Cambridge.

See the licence plan for the rules on third-party libraries and on studying other software.