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.SMF file extension

To open .SMF files on Windows, install Apache OpenOffice (Math) or LibreOffice.

To open an .SMF file, use a math/formula editor that supports StarMath (StarOffice/OpenOffice Math), such as Apache OpenOffice Math or LibreOffice. If your system doesn’t recognize it, don’t rename the extension—open it from within the office suite or set the file association.

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Last updated: June 10, 2026 · Reviewed by Julian Stricker

What “reviewed” means on this page
  • Format fit: whether the “what is this file?” description matches common real-world use of the extension, including category, typical MIME types, and aliases.
  • Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps; we remove fantasy menus and unsafe shortcuts.
  • Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
  • Sources and further reading: whether external links point to vendors, standards bodies, or other primary references where possible; we avoid inventing details we cannot ground.
  • Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless.

Full methodology in the Imprint — The Imprint also states where AI is used and what that does—and does not—replace.

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .SMF files

Use these platform-specific instructions to open .SMF files safely.

Windows

  1. Install Apache OpenOffice (Math) or LibreOffice.
  2. In the suite, open the file (e.g., File → Open) and select the .SMF document; or right-click the file → Open with → choose OpenOffice/LibreOffice and optionally set it as the default.
Full Windows guide

Mac

  1. Install LibreOffice (commonly used for StarMath/StarOffice Math files) or Apache OpenOffice if available for your setup.
  2. Open LibreOffice/OpenOffice first, then use File → Open to select the .SMF file (or Control-click → Open With → choose the office suite).
Full Mac guide

Linux

  1. Install LibreOffice or Apache OpenOffice from your distribution’s repositories or the vendor packages.
  2. Open the file from within the suite (File → Open) or set the default app in your file manager to open .SMF with LibreOffice/OpenOffice.
Full Linux guide

iOS

  1. iOS typically won’t open StarMath .SMF files directly; transfer the file to a desktop system and open it with LibreOffice or Apache OpenOffice.
Full iOS guide

Android

  1. Android typically won’t open StarMath .SMF files reliably; move the file to a PC/Mac/Linux device and open it with LibreOffice or Apache OpenOffice.
Full Android guide

Security notes

  • Because .SMF is an office-document format opened by complex parsers, only open .SMF files you trust—malformed documents can potentially trigger vulnerabilities in document-reading software.
  • The .smf extension is known to be used for multiple file types; if you receive an .SMF unexpectedly, verify the sender and context before opening it in any application.
  • Prefer opening .SMF in up-to-date versions of LibreOffice or Apache OpenOffice to benefit from the latest security fixes.

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Can't open this file?

These are the most common causes and fixes when .SMF files fail to open.

Common reasons

  • The .SMF file won’t open or shows an “unknown format” error
  • The file opens but the formula is missing or looks corrupted
  • Double-click opens the wrong app

Fix steps

  1. Install or update LibreOffice or Apache OpenOffice and try opening the file from inside the suite (File → Open).
  2. Confirm the file’s origin: if it did not come from StarOffice/OpenOffice/LibreOffice Math-related workflows, it may be a different .SMF variant.

OS-specific troubleshooting

What is a .SMF file?

.SMF is most commonly a StarMath (StarOffice/Apache OpenOffice Math) formula file. Sources associate it with the media type application/vnd.stardivision.math and the StarOffice/StarMath ecosystem. Some websites note the .smf extension has multiple uses, so confirm the file’s origin if it doesn’t look like a formula document.

Background

In the OpenOffice/StarOffice world, .SMF is used for math formula documents created or edited with the Math component (often referred to as StarMath). This format is documented in vendor MIME/extension lists as application/vnd.stardivision.math with the .smf extension.

In practical terms, .SMF files are typically exchanged as part of office-document workflows (e.g., formulas created in a math editor and stored as separate formula files). They are generally opened via an office suite rather than by generic archive tools.

Be aware that the .smf extension is ambiguous in the wider file ecosystem. If an .SMF file fails to open in OpenOffice/LibreOffice, it may be a different kind of file that happens to share the same extension; check where you got it and what application produced it.

Common MIME types: application/vnd.stardivision.math

Further reading

Authoritative resources for more details on the .SMF format.

Common .SMF issues

The .SMF file won’t open or shows an “unknown format” error

This often happens when no StarMath-compatible software is installed, or when the file is not actually a StarMath formula despite using the .smf extension.

  1. Install or update LibreOffice or Apache OpenOffice and try opening the file from inside the suite (File → Open).
  2. Confirm the file’s origin: if it did not come from StarOffice/OpenOffice/LibreOffice Math-related workflows, it may be a different .SMF variant.

The file opens but the formula is missing or looks corrupted

The file may be incomplete (bad transfer/download) or damaged, which can prevent the math document from parsing correctly.

  1. Re-copy or re-download the .SMF file from the original source and try again.
  2. Try opening it in an alternative compatible suite (e.g., LibreOffice if OpenOffice fails, or vice versa).

Double-click opens the wrong app

Your OS may have associated .SMF with another program (especially because the extension is known to be used for multiple file types).

  1. Use “Open with” to select LibreOffice or Apache OpenOffice, and set it as the default for .SMF.
  2. If the file still doesn’t open correctly, treat it as an ambiguous extension and verify what created it.

FAQ

Is .SMF an archive file?

In the sources cited here, .SMF most commonly refers to StarMath (StarOffice/OpenOffice Math) formula files, not a general-purpose archive format.

What program opens .SMF files?

StarMath-compatible software such as Apache OpenOffice (Math) and LibreOffice can open the common StarMath .SMF format.

What is the MIME type for StarMath .SMF?

Sources list application/vnd.stardivision.math for StarOffice/StarMath .SMF files.

Can I convert an .SMF file by renaming it?

No. Renaming only changes the extension label. Use an office suite that can open the file and then export/save to another format if supported.

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