How to convert SLK to XLSX
- Add your .SLK file - drop it in the box above or click to browse.
- Convert it to .XLSX in a few seconds.
- Download your new .XLSX file.
What to expect
- Formulas stored in the
.slkare parsed correctly and remain fully functional in the resulting.xlsx. - Do not open
.slkfiles from untrusted sources - SYLK can embed formula records that execute on open, a vector exploited in real phishing campaigns. - The Excel error "SYLK: File format is not valid" is caused by a CSV whose first cell reads
ID, not by a corrupt.slkfile.
Frequently asked questions
Do formulas survive the conversion?
Yes. SYLK stores formulas as text records and both Excel and LibreOffice parse them into native
.xlsx formulas that work normally after conversion.Is the conversion lossless?
For what SYLK can actually store - cell values, basic number formats, and formulas - yes. Charts, images, and advanced styles fall outside the SYLK spec, so nothing on that level is lost.
Excel shows "SYLK: File format is not valid" when I open my file - why?
That error appears when Excel encounters a file whose first cell is literally
ID and mistakenly tries to parse it as SYLK. If the file is a genuine .slk, try opening it in LibreOffice Calc instead.Can I convert multiple SLK files at once?
Yes - LibreOffice's command-line mode accepts wildcards:
libreoffice --headless --convert-to xlsx *.slk processes all files in one pass.Programs that convert SLK: Microsoft Excel · Corel Quattro Pro · PlanMaker · Microsoft Excel for Mac · NeoOffice · Apache OpenOffice Calc (OpenOffice.org Calc) · LibreOffice Calc
