Free online WKS to XLSX converter

Older records and backups may contain Microsoft Works spreadsheets that current Excel cannot open directly. Converting the file to .xlsx makes its data usable in modern Excel, LibreOffice Calc, and other current spreadsheet applications.

What the WKS format is

.wks is a binary spreadsheet format associated primarily with Microsoft Works, a discontinued office suite used by home users and small businesses. A Works spreadsheet can contain tables, formulas, numbers, dates, basic formatting, and limited charts.

Some older Lotus spreadsheet products also used the .wks extension. Confirm the file's source if an importer rejects it or displays incorrect data; changing the extension does not change the underlying format.

What the XLSX format is

.xlsx is the ZIP-packaged, XML-based workbook format used by current Microsoft Excel. It supports multiple worksheets, formulas, formatting, charts, tables, filters, and substantially larger worksheet dimensions than the Works format.

XLSX is suitable when a workbook must be edited in current Excel, shared with other users, imported into business software, or stored in a format supported by modern office applications. Its internal structure and feature set differ from WKS, so conversion is not guaranteed to preserve every detail.

How to convert WKS to XLSX

LibreOffice Calc is the most practical desktop option when its Works import filter recognizes the file:

1. Install a current desktop version of LibreOffice and open Calc.
2. Select File → Open, choose the .wks file, and let Calc select the import filter. If a filter list appears, choose the Microsoft Works spreadsheet option rather than a similarly named text or database format.
3. Check sheet names, cell values, formulas, dates, number formats, column widths, merged cells, and charts.
4. Select File → Save As and choose Excel 2007–365 (*.xlsx) as the file type. Save to a new filename so the original WKS file remains unchanged.
5. When Calc warns that some features may not be preserved, choose the option to use the Excel 2007–365 format.

Current Microsoft Excel generally does not provide native support for opening old Microsoft Works spreadsheet files. If LibreOffice cannot identify the file, verify that it is a Works spreadsheet and not a Lotus file with the same extension; an older application capable of reading the source format may be required before saving to XLSX.

You can also convert the file on 101convert.com for free without installing software: upload the WKS file, select XLSX, start the conversion, and download the resulting workbook. Avoid uploading confidential or regulated data unless the service's privacy and retention terms are acceptable.

Quality and compatibility checks

WKS stores fewer spreadsheet features than XLSX. After conversion, compare important totals with the original, inspect formula results, and verify dates, decimal separators, negative numbers, merged cells, page layout, charts, and fonts. Open the output in the application that will be used for editing and recalculate formulas there.

Works-specific formatting and older chart behavior may change, and unsupported formulas may become values or require correction. External references, links, or other features that depend on the original Works environment may not function in XLSX. Keep the original WKS file as the archival source and treat the XLSX file as the editable working copy.