File & internet
XLSX to CSV
Convert a selected worksheet in an Excel workbook locally, with explicit date and formula handling. Nothing you enter leaves your browser.
The selected file is processed only in this browser. No upload is made.
Your result will appear here.
What this tool does
About the XLSX to CSV
This converter transforms supported XLSX input into CSV. Review the supported scope below, especially when the target format cannot represent all source features.
It is designed for quick file and network calculations without sending the selected file to an application server.
How to use it
- Choose the source file in the workbench.
- Dates can be set to ISO dates and times, Original Excel date serials. Then select “Convert to CSV.”
- Inspect the result. Download the new file when available, or copy the text result. Keep the original until you have verified the converted copy.
Practical example
Start with a known input
Try this sample input: Use the pre-filled sample values in the workbench. Select “Convert to CSV” and compare the result with the source before using it elsewhere.
What to know about the result
- Choose a worksheet after selecting a file. Dates can be ISO text or original serials. Formulas use saved results or formula text; recalculation is not performed. Blank row positions are retained.
- CSV is designed for rows and columns. Nested values must be flattened or represented as text, and quoting is used when a cell contains a comma, quote, or line break.
- XLSX is a workbook format. Choose which worksheet to convert and use the first row as column names where a table structure is required.
- Dates can be set to ISO dates and times, Original Excel date serials.
Common questions
Using the XLSX to CSV
Is the XLSX to CSV free to use?
Yes. FormatCalc's XLSX to CSV is free to use with no account required.
Is my data private when I use the XLSX to CSV?
Yes. This tool processes your input locally in your browser. FormatCalc does not upload or store what you enter.
How do I use the XLSX to CSV?
Choose or paste your file data, then choose Convert to CSV. The conversion stays on your device.
What should I check before using the result?
Choose a worksheet after selecting a file. Dates can be ISO text or original serials. Formulas use saved results or formula text; recalculation is not performed. Blank row positions are retained. CSV is designed for rows and columns. Nested values must be flattened or represented as text, and quoting is used when a cell contains a comma, quote, or line break. XLSX is a workbook format. Choose which worksheet to convert and use the first row as column names where a table structure is required. Dates can be set to ISO dates and times, Original Excel date serials.