Free online WK1 to CSV converter

A newer spreadsheet, database, or data-analysis program may not open a legacy .WK1 file, while CSV is widely accepted for importing tabular data. Converting the file also provides a practical way to share or archive its cell values without requiring Lotus 1-2-3.

What the WK1 format is

.WK1 is the binary worksheet format used by Lotus 1-2-3 version 2. It can contain cell values, formulas, labels, and limited worksheet formatting. WK1 files are most often found in DOS-era accounting, inventory, engineering, and office archives or during migrations from Lotus 1-2-3.

Current versions of Microsoft Excel generally do not support WK1 directly. LibreOffice Calc and Gnumeric may open many WK1 files, but support depends on the file's exact contents and the software version.

What the CSV format is

CSV is a plain-text tabular format. Each record normally occupies one line, and fields are separated by a delimiter, usually a comma. CSV is compact and supported by spreadsheet applications, databases, reporting systems, and programming tools.

CSV stores values and field boundaries, not a spreadsheet's presentation or behavior. It does not preserve cell formatting, charts, column widths, print settings, macros, comments, or editable formulas. A WK1 worksheet is normally exported as one flat table; a CSV file cannot represent multiple worksheets in one standard file.

How to convert WK1 to CSV

Using LibreOffice Calc

1. Install a current desktop version of LibreOffice and open Calc.
2. Choose File → Open and select the .WK1 file. If Calc does not recognize it, confirm that the file is a Lotus 1-2-3 worksheet and try Gnumeric or a compatible legacy Lotus 1-2-3 installation.
3. Inspect the imported worksheet for missing columns, altered dates, incorrect decimal separators, broken characters, and formulas that did not calculate correctly.
4. If the source contains formulas, recalculate it before exporting when the CSV must contain current calculated results. CSV usually receives the displayed or calculated values, not editable formulas.
5. Choose File → Save As, select Text CSV (.csv), enter an output filename, and select Save.
6. In the CSV export dialog, select the delimiter required by the receiving program, normally comma, and use double quotes as the text delimiter. Select UTF-8 when the data includes accented or other non-ASCII characters.
7. Reopen the resulting .csv file in a text editor or spreadsheet program and verify the column count, line breaks, dates, numbers, and quoted fields.

Using the built-in converter

You can convert the file on 101convert.com for free without installing software: upload the WK1 file, choose CSV as the output format, start the conversion, and download the result. Do not upload confidential financial, personal, or regulated data unless the service's privacy and retention conditions are acceptable.

Compatibility and data limitations

• Formatting is discarded: colors, fonts, borders, merged cells, widths, charts, print settings, comments, and other presentation features do not belong in CSV.
• Formulas need checking: unsupported Lotus 1-2-3 functions may import incorrectly, and an exported CSV may contain results rather than formulas.
• Dates and numbers have no data types: a receiving program may interpret dates as text or swap decimal and thousands separators. Check locale settings and inspect representative values.
• Delimiters are significant: fields containing commas, line breaks, or quotation marks must be quoted and escaped correctly. Use the export dialog rather than manually replacing separators.
• Encoding can change: older WK1 files may use a legacy character set. If characters are corrupted, try the appropriate source encoding and export as UTF-8 when the destination supports it.
• One worksheet per file: if the data was opened in a workbook containing multiple sheets, export each required sheet separately and use distinct filenames.