What is the CDF file format?
A .cdf file is a Computable Document Format document created by Wolfram Research. It is a plain UTF-8 text file encoding a Wolfram Language Notebook[] expression - the same underlying syntax as a .nb Wolfram Notebook - typically identified by a content-type comment near the top: (* Content-type: application/vnd.wolfram.cdf.text *).
CDF was launched in July 2011 as a distribution format for interactive Wolfram Notebooks. Its purpose was analogous to PDF for static documents: a reader without a Mathematica licence could download the free CDF Player and interact with sliders, buttons, and live computations embedded in the file. A .cdf document can contain typeset mathematics, graphics, data visualisations, and interface controls that execute Wolfram Language code on demand.
Wolfram Research declared CDF a legacy format in 2021. The dedicated CDF Player was superseded by Wolfram Player and Wolfram Player Pro, both of which handle .cdf and .nb files. Mathematica and Wolfram Desktop continue to open and author CDF files.
The format has no fixed binary magic bytes, no compression, and no encryption. File size typically ranges from tens of kilobytes to a few megabytes depending on embedded graphics and precomputed outputs.
Security & safety
RISK: MEDIUMCDF files execute Wolfram Language code when opened in Wolfram Player or Mathematica. Wolfram Player restricts allowed operations (no file system access, no network calls) - so opening a CDF in Wolfram Player is relatively safe. Opening a .cdf in full Mathematica removes those restrictions. Only open CDF files from trusted sources. The .cdf extension is also used by NASA's Common Data Format (completely different binary format) and Microsoft's obsolete Channel Definition Format - confirm file origin.
Format details
in a nutshell- Common Data Format (NASA/GSFC) - NASA's CDF is a completely unrelated binary scientific data format (.cdf) for multidimensional data; developed at Goddard Space Flight Center since 1985 and widely used in space physics.
- Channel Definition Format (Microsoft) - Microsoft's 1997 XML-based push-channel format for Internet Explorer 4 (Active Channels); long obsolete.
Programs that open CDF files
Windows4 apps
CDF Player
Free Legacy dedicated viewer (still downloadable but superseded by Wolfram Player). Double-click .cdf to open. 
Wolfram Player
Free Download Wolfram Player; double-click the .cdf file or File > Open. Interact with sliders/buttons. Replaces old CDF Player.
Wolfram Player Pro
Paid Superset of Wolfram Player; also opens .nb files and allows editing. File > Open. 
macOS3 apps
Linux2 apps
Technical details
deep spec| Encoding | Plain ASCII / UTF-8 text - Wolfram Language expression syntax |
| File structure | Wolfram Language `Notebook[]` expression with `Cell[]` objects - text, typeset math, graphics, and interface controls |
| File identification | Content-type comment near top of file: `(* Content-type: application/vnd.wolfram.cdf.text *)` |
| Relationship to .nb | Structurally a constrained subset of Wolfram Notebook (`.nb`) format; opens in the same applications |
| Interactive elements | Sliders, buttons, and other controls that execute live Wolfram Language computations when activated |
| MIME type | `application/vnd.wolfram.cdf`; also `application/vnd.wolfram.cdf.text` |
| Magic bytes | None - plain text identified by content-type comment, not a binary signature |
| Legacy status | Declared legacy by Wolfram Research in 2021; superseded by `.nb` opened via Wolfram Player / Wolfram Player Pro |
| Original purpose | Distribution of interactive Wolfram Notebooks to readers without a Mathematica licence (analogous to PDF for static documents) |
| Typical file size | Tens of KB to several MB depending on embedded graphics and precomputed outputs |
| Platform support | Windows, macOS, Linux (via CDF Player / Wolfram Player / Wolfram Player Pro) |
| Released | July 2011 (officially launched by Wolfram Research) |
| Latest version | N/A - CDF marked legacy in 2021; replaced by Wolfram Computational Notebooks (.nb) |
| Open standard | Yes · royalty-free |
| Specification | reference.wolfram.com |
CDF conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about CDF files.
