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Document format

XLSM converter

An .xlsm file is a Microsoft Excel workbook that is allowed to carry VBA macros. The grid itself is stored exactly as in an .xlsx package — SpreadsheetML worksheets plus a shared-string table — with one extra part holding the compiled macro project.

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Drop XLSM files here

Batch files can each use a different output. Nothing uploads for local conversions.

Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.

Where XLSM comes from

Excel 2007 split the old .xls extension in two, giving .xlsx a hard guarantee that it contains no executable code and moving anything with VBA to .xlsm. Excel macros remain the single most exploited document attack surface, which is why Microsoft went on to block macros in files marked as internet-sourced by default in 2022.

How XLSM works

  • Same OOXML package as .xlsx: xl/worksheets/sheetN.xml, xl/sharedStrings.xml, styles, and a workbook relationship graph.
  • Macros live in xl/vbaProject.bin as a compiled OLE-packaged VBA project.
  • A workbook may also declare Excel 4.0 macro sheets under xl/macrosheets, an older and separately abused mechanism.
  • Novus Convert deletes xl/vbaProject.bin and every xl/macrosheets part before parsing, and reads only parts under xl/worksheets, so no macro of either kind is read, interpreted, or executed.
  • Cell values are taken from the results already cached in the file; nothing is recalculated.

When to use XLSM

  • Financial models and reporting workbooks with automated refresh or formatting.
  • Data-entry tools built for a team with validation logic behind them.
  • Extracting the data out of an inherited macro workbook as CSV or JSON.
  • Converting a macro workbook to plain .xlsx so it can pass a security policy.

Strengths and limitations

Strengths

  • Extension makes macro capability explicit, so gateways and scanners can triage.
  • Full .xlsx grid limits and the same open, documented package anatomy.
  • Automation travels with the data instead of living in a separate add-in.

Limitations

  • The most heavily abused document format in phishing campaigns.
  • Blocked by default in many organizations and by Excel itself for internet-sourced files.
  • Macros are version- and platform-fragile, and do not run in Excel for the web.

Compatibility

Excel 2007 onward on Windows and macOS opens .xlsm with a macro prompt. LibreOffice Calc reads the grid and runs a subset of VBA; Google Sheets and Excel for the web import the data and discard the macros. Apple Numbers imports the values only. Conversion here reads the cells and leaves the macro behind.

docProps/core.xml and docProps/app.xml carry author, dates, and the generating application; tabular exports such as CSV keep none of it.

Convert XLSM to another format