How to Convert Excel (XLSX) to CSV Without Excel

An XLSX file is a ZIP archive of XML documents (the Office Open XML format) describing worksheets, formulas, formatting, charts, and metadata. A CSV is a plain text file: one row per line, values separated by commas. That gap means conversion is inherently lossy — and knowing what's lost prevents surprises:

• Only one sheet survives: CSV has no concept of multiple worksheets. A workbook with five sheets needs five CSV files.
• Formulas become their current values: =SUM(A1:A10) exports as whatever it last evaluated to.
• All formatting disappears: colors, borders, column widths, merged cells, conditional formatting — gone.
• Data types flatten to text: dates and numbers export as they're displayed, which is where most real-world corruption happens (more below).

None of this is a flaw — it's the point. CSV's simplicity is why every database, script, and import wizard on Earth accepts it.

1. 1

   Open FileMorf's converter and switch to the document tab

   The document converter handles XLSX, ODS, CSV, and other tabular formats — no account needed.

2. 2

   Drop in your .xlsx file

   The spreadsheet is parsed locally in your browser. Unlike upload-based converter sites, the file never leaves your device — relevant when the spreadsheet is a customer list or financial data.

3. 3

   Choose CSV as the output and download

   You get a clean UTF-8 CSV ready for imports, scripts, or databases.

Three other free routes, each with a legitimate niche:

• Google Sheets (any browser): upload the XLSX to Google Drive, open with Sheets, then File → Download → Comma Separated Values. Exports the active sheet only. Works anywhere, but note you are uploading the data to Google — fine for most files, a policy question for confidential ones.
• LibreOffice Calc (Windows/Mac/Linux, free): open the file and Save As → Text CSV. Its export dialog exposes delimiter, quoting, and encoding options Excel itself hides — genuinely the most control of any GUI method. The suite is a ~350 MB install.
• Command line for batches: LibreOffice headless converts entire folders (soffice --headless --convert-to csv *.xlsx), and csvkit's in2csv (Python) is ideal in data pipelines — in2csv data.xlsx > data.csv, with a --sheet flag for specific worksheets.

Most 'the conversion broke my data' reports trace back to four well-known traps:

• Encoding: accented characters (é, ü, ñ) or non-Latin text turning into garbage means an encoding mismatch. Export as UTF-8. Ironically, Excel itself misreads plain UTF-8 CSVs unless they start with a BOM (byte order mark) — if your CSV's consumers include Excel users, prefer 'CSV UTF-8' style output.
• Regional delimiters: in much of Europe, the decimal separator is a comma, so 'CSV' files locally use semicolons as field separators. If your target system expects commas and gets semicolons (or vice versa), every row lands in one column.
• Leading zeros: ZIP codes, phone numbers, and product IDs like 00420 survive the conversion as text — the mangling usually happens later, when the CSV is re-opened in a spreadsheet app that 'helpfully' parses them as numbers. The same is true of the infamous gene-name-to-date bug: it's a re-import problem, not a conversion problem.
• Dates: CSV stores dates as displayed text. If the sheet displays 03/04/2026, is that March 4 or April 3? For machine consumption, reformat date columns to ISO (2026-04-03) before exporting — future you will be grateful.

The reverse trip — CSV to a formatted spreadsheet — is just as common, and the same tools handle it. FileMorf's document converter also covers the neighboring conversions that show up in data work: CSV to JSON for APIs, JSON to CSV for flattening exports, XML to CSV for legacy feeds, and CSV to PDF when someone upstream wants something printable. All of it runs client-side in the browser.