ConvertRS Private browser tools
ES
Local, private conversion

Convert XLS to XLSX privately

Drop your XLS file, preview the XLSX result locally, and download without uploading your file.

Stays in your browser Adjust before saving PDF Studio included
Common source formats
AVIFBMPCSVDOCXGIFHTMLICOJPG

How to convert XLS to XLSX

Convert XLS to XLSX locally in your browser. The file is read on your device, rewritten for the selected format, and downloaded without an upload step.

Steps

  1. Drop or choose your XLS file.
  2. Confirm XLSX as the result format.
  3. Preview the result when available, then download the converted file.

Best for

  • Extracting legacy Excel rows to CSV, TSV, or JSON.
  • Extracting workbook rows to CSV, TSV, or JSON.
  • Private browser-based conversion without an upload step.

What changes

  • Extracting workbook rows to CSV, TSV, or JSON.
  • Tabular values are written to the first XLSX worksheet.
  • Source formatting, formulas, charts, images, comments, and macros are not included.
  • Nested JSON values are stored as compact JSON text.
  • Structured values are rewritten for the selected data format.
Can I convert XLS to XLSX without uploading?

Yes. ConvertRS runs supported conversions in your browser and keeps the file on your device.

What changes when I create XLSX?

Extracting workbook rows to CSV, TSV, or JSON. Tabular values are written to the first XLSX worksheet. Source formatting, formulas, charts, images, comments, and macros are not included. Nested JSON values are stored as compact JSON text. Structured values are rewritten for the selected data format.

What happens to my original XLS file?

It stays on your device. The page reads the file locally so you can preview and download the converted result.