Private, local-first data tools
Open XLSX or XLS locally, select the worksheet you need, or download every sheet as separate CSV files in one ZIP.
The parser runs off the main thread. Once loaded, you can search, sort, validate, repair and export without an account.
A workbook can contain formatting, formulas and several worksheets. A CSV contains one text table. Choose the worksheet first, then inspect the displayed values and header names before downloading. The first row of the worksheet's used range becomes the header; it is not automatically guessed from numeric or text content.
This converter reads formatted cell text. A numeric cell containing 184with number format 000000 becomes 000184. An amount stored as 12.5 with format 0.00 becomes 12.50. A formula with a stored result of 2 contributes that result:
code,amount,total
000184,12.50,2These examples are checked by generating workbook bytes and reading the actual CSV export. They do not mean formulas are evaluated here. The reader uses saved results, which can be stale if the workbook was not recalculated before saving.SheetJS documents the distinction between formulas and stored results.
If a formula has no cached result, the preview remains available with an error naming the sheet and cell addresses. Downloads of that worksheet are blocked. Recalculate and save the workbook in a spreadsheet application, then reopen it here. Header repairs and filters cannot replace a missing calculation result.
Both download paths apply the chosen delimiter, line ending, Include header setting and UTF-8 BOM option. For example, choosing semicolons and a BOM gives each CSV in the ZIP the same encoding marker and separator as an individual sheet download. Empty headers receive column names, and duplicates receive unique suffixes in both paths.
The all-sheets ZIP always converts every original worksheet. It does not apply the current sheet's search filter, sort order or manual repairs. Each worksheet becomes a separate CSV; filenames are sanitized and numbered when necessary so two sheets cannot overwrite one ZIP entry. For only the current search results, download the selected sheet with the appropriate row scope instead.
A sheet exceeding 250,000 data rows remains a preview and cannot be exported here. The all-sheets workflow checks each original worksheet, including sheets you have not selected. An oversized sheet or a formula without a cached result stops the entire archive; the tool does not silently leave that sheet out.
Empty cells become empty fields. CSV does not retain merged-cell layout, fonts or spreadsheet formulas. Verify dates, identifiers and totals in the resulting text, using CSV Viewer for inspection andthe encoding guide when reopening CSV in Excel. To create a workbook from CSV instead, use CSV to Excel.
What this tool does
The Excel reader loads only after you choose a workbook. It lists all worksheet names, previews the selected sheet and lets you save that Excel sheet as a CSV file or package every worksheet as a separate CSV file.
Local files are read by a dedicated browser worker and are not uploaded to an application server. File contents and filenames are not included in analytics events. Loading a public URL is an explicit direct request from your browser and may fail when the remote server blocks CORS.
To save an Excel file as a CSV or export an Excel file to CSV, choose the XLSX or XLS file, select the worksheet and inspect its stored values, then download that sheet. You can create a CSV file from the selected Excel worksheet, or download every sheet in one ZIP.
No. CSV has no sheet concept. Select one worksheet or download all worksheets as separate CSV files in a ZIP.
No. The converter reads the values stored in the workbook; it does not run Excel's calculation engine.
Yes. Both XLSX and legacy XLS files can be opened in the browser.