A free ChemDraw alternative that opens your ChemDraw files
Athanor is advanced, state-of-the-art chemistry drawing and visualization software by arbastro, and a free ChemDraw alternative with a very generous free plan. It opens CDX and CDXML files as they are and saves back to both, so you can switch without redrawing anything and still send ChemDraw users a file they can open.
ChemDraw Prime costs $700 a year and Professional $1,355 a year. Athanor is free, including for commercial work and publication.
Windows 10 and 11 Updates itself from the Store
Runs in your browser. No account needed to draw.
CDX and CDXML in and out
Open ChemDraw files directly and save them back out, beside MOL, SDF, RXN and SMILES.
Journal document styles
21 presets, including ACS Document 1996, RSC one and two column, Wiley and Nature Research.
Things ChemDraw does not do
Products predicted as you draw, retrosynthesis back to buyable starting materials, animated mechanisms, and problem sets that grade themselves.
Runs in a browser
The whole editor works in the browser with nothing to install, on any operating system. There is also a Windows app.
An open file format
An .athanor file is a ZIP with every structure inside as a standard MOL V3000 file.
Names and stereo
R/S and E/Z labels by the full CIP rules as you draw, and IUPAC names you can check against OPSIN in one click.
What ChemDraw still does better
ChemDraw still does more in a few places; the table below lists them under “Where others do more”. If those are central to your work, keep ChemDraw for them: Athanor reads and writes its files, so the two work side by side.
Athanor, ChemDraw and the others, row by row
Swipe the table to see every tool
 Athanor | ChemDraw | ChemDoodle | Marvin | Octet Draw | Discontinued Aug 2026ChemSketch | |
|---|---|---|---|---|---|---|
| Price & access | ||||||
| Price | Free | Prime $700/yrProfessional $1,355/yr | $199/yror $999 lifetime | $29/mo academic$99/mo commercial | Free | No longer sold |
| Free for commercial work | – | – | – | – | ||
| Full editor in the browser | Enterprise plan | Developer toolkit | – | – | ||
| Prediction | ||||||
| Products predicted as you draw | – | From arrow pushing | – | – | – | |
| Retrosynthesis route planning | – | Manual disconnections | – | – | – | |
| Property prediction | Basic | |||||
| AI assistant that draws and animates | – | – | – | – | – | |
| Teaching | ||||||
| Problem sets with automatic grading | 21 question types | – | – | – | – | – |
| Mechanism checking | – | – | – | – | – | |
| Moodle XML and QTI export | – | – | – | – | – | |
| Drawing & visualization | ||||||
| 2D structure drawing | ||||||
| 3D models | – | |||||
| Orbitals and MO diagrams | Orbital palette | – | – | – | ||
| Animated mechanisms | – | – | – | – | – | |
| Biopolymers (HELM, peptides, DNA) | – | – | – | – | ||
| Data & workflow | ||||||
| Compound library with cited safety data | PubChem add‑in | – | – | – | – | |
| Live collaboration | In testing | Enterprise plan | – | – | – | – |
| Opens ChemDraw files | ||||||
| Name to structure for any IUPAC name | Online | Offline | – | |||
| Platforms | ||||||
| Desktop app | Windows | Windows, Mac | Windows, Mac, Linux | Windows, Mac, Linux | Windows | |
| Mac and Linux | In the browser | Mac | – | |||
| Works offline | Desktop app | Desktop | ||||
| Open source | – | – | – | – | Apache‑2.0 | – |
| Where others do more | ||||||
| ¹H and ¹³C NMR prediction | Predicted, AI | – | ||||
| Fully offline, no account | – | – | ||||
| Office and ELN integration | – | LabArchives | Office, on Mac | – |
Prices as of October 2026, from each vendor’s own page. Check with the vendor before you buy.
Sources