Convert XLS to ASCII

Legacy applications, scientific instruments, mainframes, and command-line scripts may accept only delimited plain text instead of an Excel workbook. Converting the workbook produces a smaller file that can be transferred, archived, or imported by systems that do not support spreadsheet formats.

What the XLS format is

.xls is Microsoft Excel's binary workbook format, used mainly by Excel 97–2003 and compatible spreadsheet programs. An XLS file can contain multiple worksheets, formulas, formatting, charts, comments, named ranges, macros, and embedded objects.

Microsoft Excel, LibreOffice Calc, Apache OpenOffice Calc, and other spreadsheet applications can open XLS files. Because an XLS workbook is not a single plain data table, conversion must define which worksheet to export and how to represent its cells.

What ASCII means

ASCII is a 7-bit character encoding and a plain-text representation, not a spreadsheet container. Standard ASCII has 128 characters: control characters, letters, digits, punctuation, and spaces. An ASCII text file has no formulas, fonts, colors, merged-cell metadata, charts, images, or multiple worksheets.

Spreadsheet data is usually written as tab-delimited or comma-delimited records. A file such as customers.txt can use one row per record and a tab between fields; customers.csv normally uses commas, quotation marks, and defined escaping rules. CSV is often called ASCII informally, but it is strictly ASCII only when every character is within the 7-bit ASCII range.

Plain text works with legacy import programs, Unix utilities, database loaders, fixed-format devices, source-control systems, and archival workflows. It is human-readable and independent of spreadsheet software, but it cannot preserve workbook structure.

How to convert XLS to ASCII

With Microsoft Excel

1. Open the workbook and select the worksheet to export. Excel's text formats generally export only the active worksheet.
2. Choose File → Save As, select a destination, and choose Text (Tab delimited) (*.txt).
3. Save the file, for example as report.txt, and accept the warning about features that cannot be saved in a text format.
4. Open the result in a plain-text editor and check delimiters, line endings, dates, decimal separators, and character encoding.

For comma-delimited output, choose CSV (Comma delimited) (*.csv). CSV is often more suitable for database imports, but the resulting file is not necessarily strict ASCII; its encoding may be a system code page or a Unicode-compatible variant. If the target requires tabs, use the tab-delimited option instead of renaming a CSV file.

With LibreOffice Calc

1. Open report.xls in Calc and select the required worksheet.
2. Choose File → Save As, use a .csv or .txt filename, and select Text CSV (.csv) as the file type.
3. In the export dialog, select US-ASCII when the receiving system requires strict ASCII. Set the field delimiter to the required tab, comma, semicolon, or other character, and set the text delimiter to a double quote when quoted fields are required.
4. Enable Quote all text cells only if the target specification requires it, then save and inspect the output.

LibreOffice is a suitable free desktop option because its export dialog exposes encoding, delimiter, and quoting settings. For batch work, a basic command is libreoffice --headless --convert-to csv --outdir output report.xls; verify the active-sheet behavior, encoding, delimiter, and output values before using it in production.

With an online converter

Reputable services such as CloudConvert and Zamzar can convert an uploaded XLS file to CSV or TXT when browser-based processing is required. Choose a delimited plain-text output, download it, and inspect or re-encode it locally if strict US-ASCII is required. Do not upload confidential, regulated, or proprietary workbooks unless the provider's retention, deletion, and processing terms are acceptable.

Quality and compatibility limits

• Only the active worksheet may be exported. Export each sheet separately when the destination needs the complete workbook.
• Formulas normally become their calculated, displayed results rather than remaining formulas. Recalculate the workbook before export if current values matter.
• Formatting, colors, merged-cell structure, charts, images, comments, macros, validation rules, and workbook relationships are discarded.
• Strict ASCII cannot represent accented letters, the euro sign, smart quotation marks, or most non-Latin scripts. Replace unsupported characters deliberately, or use UTF-8 when the receiving system supports it. An ASCII export setting may substitute unsupported characters, so inspect the result.
• Dates and numbers can change meaning through locale-specific display rules. Set an unambiguous date format such as YYYY-MM-DD, and verify decimal and thousands separators.
• Leading zeros in identifiers, long integers, dates, and scientific notation require special checking. Do not reopen the exported file in a spreadsheet without specifying column types, because the spreadsheet may reinterpret values.
• Cells containing tabs, commas, quotation marks, or line breaks require the delimiter and quoting rules expected by the target. Use fixed-width output or a dedicated export script when the destination specifies exact column positions.
• Inspect the result with a plain-text editor or encoding tool rather than relying only on a spreadsheet application, which may hide malformed delimiters or silently reinterpret values.