LOCAL DATA CONVERTER / XLSX TO CSV

Excel to CSV

Export the first or every worksheet from an XLSX workbook as UTF-8 CSV without executing workbook formulas or macros.

Processed in this browserOne unencrypted .xlsx file up to 15 MB, up to 50 sheets; each exported sheet is limited to 100,000 rows and 1,000 columns.

Step 1 / source

Choose the source

XLSX - 15 MB

Drop one file here

Choose a modern XLSX workbook. Legacy XLS, encrypted workbooks, and macro execution are not supported.

Browse filesChecking publication status...

No file upload

This operation runs with browser APIs. Nirmion receives catalogue requests, not the selected source bytes.

Original stays unchanged

The converter creates a separately named output. It never writes back into the source file.

Bounded work

One unencrypted .xlsx file up to 15 MB, up to 50 sheets; each exported sheet is limited to 100,000 rows and 1,000 columns.

Plain-language method

What survives the CSV boundary

The browser reads workbook cell values and writes one comma-separated table per selected worksheet. Styling, merged-cell appearance, charts, comments, and formulas cannot exist in CSV.

01
Choose a valid source
Use an unencrypted XLSX workbook. Save calculated formulas in the source application if current displayed results matter.
02
Review the conversion choices
First sheet creates one CSV. All sheets creates a ZIP. Formula protection is enabled by default for text that could execute when reopened in spreadsheet software.
03
Inspect the separate result
Single-sheet output ends in _nirmion_tools.csv; all-sheet output ends in _nirmion_tools_csv_sheets.zip.

Useful when

Practical jobs this tool handles

Move worksheet values into a database import.
Export every sheet for code or data analysis.
Create plain-text snapshots of workbook data.

Before converting

Review workbook-only features

Recalculate and save formulas in the source application first.
Check merged cells and hidden rows because CSV has no visual layout.
Keep formula protection enabled unless exact formula-leading text is required.

Know the boundary

CSV stores values, not a workbook

Formatting, formulas, charts, images, multiple tables, and cell comments are not preserved. Cached formula results may be blank when the workbook was not previously calculated.

Quick answers

Questions before you convert

Export choices control how much of the workbook is flattened.

Are formulas executed?

No. The parser uses stored formula results when present and does not run workbook code.

Why is all-sheets output a ZIP?

CSV can hold only one table, so each worksheet needs its own file.

What does formula protection do?

It prefixes formula-leading text values so spreadsheet software is less likely to execute them when the CSV is opened.