Free online 123 to XLSX converter

Legacy Lotus 1-2-3 files often need conversion when current spreadsheet software requires .xlsx for editing, sharing, or archiving. Converting the workbook also avoids requiring recipients to install or maintain Lotus 1-2-3.

What the 123 format is

.123 is a legacy spreadsheet workbook format associated with Lotus 1-2-3, an office application used for budgets, accounting, reports, calculations, and business records. These files usually come from older DOS or Windows systems, organizations that retained Lotus software, or archives migrated from earlier office suites.

A 123 workbook can contain worksheets, labels, numbers, formulas, cell formatting, charts, print settings, and named ranges. It uses a binary structure designed for Lotus 1-2-3, and support in current spreadsheet applications depends on the specific Lotus file variant and the application version.

What the XLSX format is

.xlsx is the XML-based workbook format used by modern Microsoft Excel and supported by LibreOffice Calc, Apple Numbers, Google Sheets, and other spreadsheet applications. An XLSX file is a ZIP package containing XML files for worksheets, formulas, styles, charts, relationships, and workbook metadata.

XLSX is suitable when the workbook must be edited in current office software, shared through modern document systems, imported into data-analysis tools, or stored in a broadly supported format. It cannot store VBA macros; Excel workbooks containing VBA use .xlsm. Lotus 1-2-3 macros and other application-specific automation generally require rewriting rather than direct conversion.

How to convert 123 to XLSX

Using LibreOffice Calc

1. Install a current version of LibreOffice and open Calc.
2. Choose File → Open, select the .123 file, and change the file filter to show all files if necessary.
3. Confirm that Calc imported the expected worksheets, values, formulas, dates, formatting, charts, and print settings. If Calc reports that the format is unsupported, use a Lotus 1-2-3-compatible legacy application to save the file in a format Calc can import.
4. Choose File → Save As.
5. Set the output filename to end in .xlsx and select Excel 2007–365 (*.xlsx) as the file type.
6. When Calc warns about format or feature differences, choose Use Excel 2007–365 Format.

For a one-time conversion without installing software, upload the file to the free converter on 101convert.com, choose XLSX as the output format, download the result, and verify it in a spreadsheet application.

Automating with LibreOffice

If LibreOffice can open the particular 123 variant, its command-line interface can convert files without opening the graphical interface:

soffice --headless --convert-to xlsx --outdir converted legacy.123

Create the converted directory first and use a separate output directory so the source file is not overwritten. The command may fail when the installed LibreOffice build lacks an import filter for that 123 variant; opening the file in Calc first is the quickest compatibility test.

Quality and compatibility limitations

Conversion can alter unsupported Lotus 1-2-3 formulas, chart types, print ranges, page breaks, column widths, fonts, date systems, external references, hidden rows or columns, and named ranges. Some formulas may need rewriting, and unsupported formulas or features may be imported as values or omitted.

After saving, inspect every worksheet, formula result, date, number format, chart, hidden row and column, named range, external link, and print preview. Compare important totals with the original file and save the converted workbook under a new filename. Keep the original .123 file because an XLSX conversion may not preserve all legacy behavior or metadata.