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Spreadsheet Converter

Convert CSV, TSV, XLSX, and tabular JSON files locally with explicit sheet handling and a bounded preview.

Runs locally — input is never uploaded
File & optionsCSV, TSV, XLSX or JSON · max 15 MiB
Worksheet
Bounded previewReady when you are

Choose a spreadsheet to preview its first 100 rows.

WHAT IT DOES

Change the file format without flattening the workbook by accident.

Open CSV, TSV, XLSX, or tabular JSON locally, inspect a bounded table preview, choose the worksheet and header interpretation, then export CSV, TSV, JSON, or XLSX. Flat formats always use the visibly selected sheet; XLSX can preserve every sheet, so a multi-sheet workbook is never silently reduced to its first tab.

Why use it?

Use it to extract the intended worksheet or convert tabular records without sending the workbook to a remote service.

How to use this tool

  1. Open a supported table or workbook and inspect the available worksheets.
  2. Select the worksheet and header interpretation before choosing the output. For a multi-sheet workbook, CSV, TSV, and JSON export the selected sheet, not every tab.
  3. Review leading zeros, blank cells, duplicate headers, and numeric-looking identifiers in the preview. The preview is bounded and is not the whole dataset.
  4. Download the conversion and verify it in the receiving application. This tool is a data-format converter, not a promise to preserve formulas, styling, charts, or every workbook feature.

Details and limitations

  • Delimited input supports comma, semicolon, tab, and pipe detection with quoted delimiters, embedded newlines, escaped quotes, empty cells, trailing fields, UTF-8 BOM, and CRLF or LF endings.
  • XLSX input reports and exposes every worksheet. CSV, TSV, and JSON export the selected sheet only, while XLSX export can include the complete workbook or only that selection.
  • JSON accepts arrays of objects or arrays of arrays. Values are exported as display strings by default; blank and duplicate header names receive visible, deterministic JSON keys instead of overwriting data.
  • The preview renders at most 100 rows and 50 columns. Files are capped at 15 MiB, with further limits of 50 sheets, 100,000 rows, 500 columns, and 1,000,000 used-range cells per sheet.

COMMON QUESTIONS

Spreadsheet Converter questions

What happens to multiple XLSX sheets?
You can inspect each sheet. XLSX output includes all sheets by default and offers an explicit selected-sheet option. CSV, TSV, and JSON are flat formats, so they export only the sheet shown in the picker.
Are numbers and dates automatically inferred?
No. CSV, TSV, and JSON values stay strings, and XLSX cells use their formatted display text. This avoids changing identifiers, leading zeros, large numbers, and date-like text without permission.
Does conversion preserve formulas and spreadsheet styling?
No. This is a tabular data converter, not a workbook fidelity editor. It preserves displayed cell values and sheet structure, but rebuilt XLSX output does not promise formulas, charts, macros, comments, formatting, merged cells, or external links.