About Excel ↔ CSV

Convert between Excel format and CSV with format preservation. Part of the DevTools Surf developer suite. Browse more tools in the Converters collection.

Use Cases

• Convert Excel spreadsheets to CSV for database import
• Prepare CSV files from Excel exports for data pipeline consumption
• Convert CSV data to Excel for sharing with non-technical stakeholders
• Extract specific sheets from multi-tab Excel files as individual CSVs

Tips

• Use the 'sheet selector' when converting multi-sheet Excel files — each sheet can be converted independently or as separate CSV files
• Enable 'preserve formatting' to keep date and number formats visible in the CSV output — by default, dates are converted to Excel serial numbers
• The encoding selector handles files with international characters — choose UTF-8 for most modern systems, Windows-1252 for legacy Excel files from Windows environments

Fun Facts

• Microsoft Excel was first released for Mac in 1985 and for Windows in 1987. The XLSX format (Office Open XML) replaced the binary XLS format in Excel 2007 — XLSX is a ZIP archive containing XML files, which is why you can rename .xlsx to .zip and open it.
• The Excel 1900 date bug is a 36-year-old quirk: Excel incorrectly treats 1900 as a leap year (it is not), offset all dates by 1 day. Lotus 1-2-3 had the same bug, and Excel deliberately preserved the error for Lotus compatibility. The bug persists in Excel to this day.
• Gene name conversion errors caused by Excel's auto-formatting are so common that in 2020, the Human Genome Organization's HGNC working group renamed 27 human genes specifically to avoid Excel auto-converting them. MARCH1 became MARCHF1 to prevent conversion to a date.

FAQ

Why do Excel date cells become numbers in CSV?

Excel stores dates as serial numbers (days since January 0, 1900). When exported without formatting, the underlying number appears. Use 'format cells' in Excel to convert to text before exporting, or use this tool's 'preserve date format' option.

Does the converter handle merged cells?

Merged cells in Excel contain data in the top-left cell and empty cells in the rest of the merged area. In CSV conversion, the value appears only in the first cell of the merge; the others appear empty. Un-merge cells before conversion for clean CSV output.

What is the difference between CSV and TSV?

CSV (Comma-Separated Values) uses commas as field delimiters; TSV (Tab-Separated Values) uses tab characters. TSV avoids issues with commas in data fields (phone numbers, addresses) but is less universally supported. Choose based on whether your data contains commas.