Add your XLTM file
Drop one or more .xltm files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Converting a .xltm file to .xlsx extracts the document's content from its office package into a portable form. Free, private, and validated — the file never leaves your browser.
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.Converting a .xltm file to .xlsx extracts the document's content from its office package into a portable form. An .xltm file is a Microsoft Excel template that is allowed to carry VBA macros, so every workbook created from it inherits both the layout and the macro project. It is the template counterpart to .xlsm.
An .xlsx file is a modern Excel workbook — a ZIP archive of SpreadsheetML XML parts describing sheets, shared strings, styles, and formulas. It has been Excel's default save format since 2007 and the de facto interchange format for tabular business data. For this route the practical draw is vast grid limits compared with the legacy .xls format and documented ZIP-of-XML anatomy — any ZIP and XML library can mine it, which is how in-browser conversion works here — balanced against date-as-serial-number storage causes subtle off-by-one and timezone bugs, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .xltm, blocked by most mail gateways and by many corporate security policies. Switching to .xlsx buys you vast grid limits compared with the legacy .xls format, which is why it is the better fit for the standard vehicle for exchanging spreadsheets between organizations. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Macro-enabled Excel template (.xltm) | Excel workbook (.xlsx) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | same package as .xltx: workbook, worksheets, shared strings, and styles in a ZIP | xl/worksheets/sheetN.xml holds rows of typed cells; text cells usually point into xl/sharedStrings.xml to avoid repetition |
| Strongest at | departmental reporting templates with automated refresh or validation | the standard vehicle for exchanging spreadsheets between organizations |
| Weak spot | blocked by most mail gateways and by many corporate security policies | date-as-serial-number storage causes subtle off-by-one and timezone bugs |
| Metadata | standard docProps core and app parts ride in the package and are dropped by tabular exports | docProps/core.xml carries Dublin Core creator and date fields while docProps/app.xml records the generating application and company — both ride inside the ZIP |
Drop one or more .xltm files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .xlsx in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if XLSX is selectable, the route is real and validated.
Press Convert. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid XLSX file. Outputs keep the original filename with the .xlsx extension.
There is no visual quality to lose — xltm is text-oriented and xlsx is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Yes — the .xltm file is processed inside your browser tab and never uploaded. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded. Close the tab and the file is gone from memory.
Excel 2007 onward, LibreOffice Calc, Google Sheets, and Apple Numbers all handle .xlsx, and nearly every data-processing library reads it. Support is equally solid on iOS and Android through the same vendors' apps.
It depends on the content: xl/worksheets/sheetN.xml holds rows of typed cells; text cells usually point into xl/sharedStrings.xml to avoid repetition. Convert one representative file first and compare before batch-processing a large set.
In .xltm, standard docProps core and app parts ride in the package and are dropped by tabular exports. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.