Two Trees
Conversion tools

CSV ↔ Excel

Move tabular data between CSV and XLSX without uploading it.

Spreadsheet input

The first row is kept as ordinary text.

Up to 5.0 MB, 50,000 rows, 200 columns and 500,000 cells. Leading zeroes and Unicode are kept because every cell is written as text. CSV loses multiple sheets, styles and formulas.

Result

No output yet. Choose a direction, provide a local file or paste CSV, then run the conversion.

CSV to XLSX

Rows and columns are read as strings, so 00123, long identifiers and Unicode text survive. Every value is written as a text cell. A cell that begins with = is stored literally and is not turned into an executable formula. The first row is kept as ordinary text; blank or duplicate names are not renamed.

CSV cannot carry multiple sheets, cell styles, merged cells, images or formulas, so those features are absent from the new workbook. This is a one-sheet conversion.

XLSX to CSV

Upload an .xlsx workbook, choose one sheet, and export its formatted cached values. Other sheets are not included. Formula cells are never recalculated. If a formula has no cached value in the workbook, the CSV cell is blank and the result says how many cells were affected; reopen the workbook in a spreadsheet editor and recalculate it if you need those values.

The formula guard is on by default. Cells that start with =,+, @, a tab or a return are prefixed with an apostrophe so spreadsheet software treats them as text. Ordinary negative numbers such as -12.5 are left unchanged. Turn the guard off only when you trust both the workbook and the software that will open the CSV. A UTF-8 BOM option helps some desktop programs detect Unicode.

Limits and safety

  • CSV up to 5 MB, XLSX up to 10 MB compressed and about 60 MB after decompression. The workbook ZIP directory is inspected before inflation.
  • At most 50 sheets, 50,000 rows, 200 columns and 500,000 cells per selected sheet, with 32,000 characters per cell. Generated CSV or XLSX output is capped at 20 MB.
  • Legacy .xls, encrypted workbooks, unusual ZIP compression and multi-image or macro content are not supported. Macros are never run.
  • No formula is executed or evaluated anywhere in this tool.

Example

Example CSV

id,name,city
00123,Ada,"Zürich, CH"
002,李雷,東京

The workbook keeps the leading zeroes and both Unicode values as text cells.

Privacy

The workbook or CSV is read and written in this tab. Filenames, cell contents and output are not uploaded, saved to browser storage or included in analytics.