CSV → Excel (XLSX) converter

What turning a CSV into an Excel file fixes, and what to double-check

Double-click a CSV and Excel often shows garbled characters or crams every value into one column. That happens because Excel guesses the encoding and delimiter the moment it opens the file. This tool decides both up front, reads the data as a table and saves it as an XLSX workbook, so whoever receives it can open it without any guessing.

A closer look

The file is read as UTF-8 first; if broken characters (�) appear, it is read again as EUC-KR, a legacy Korean encoding, and whichever version has fewer broken characters wins. There is no Windows-1252 fallback, so a CSV saved in that encoding keeps � in place of its accented letters. The delimiter is chosen by counting commas, tabs, semicolons and pipes outside quotes in the first 1,024 characters and taking the most frequent, unless the first line says something like sep=;, in which case that character is used. The result is a standard XLSX with a single sheet named Sheet1 and no formatting such as a bold header, column widths or filters.

Each piece of CSV text gets a type as it goes into a cell. Anything that reads as a number becomes a numeric cell, so sums and sorting work at once; a value like 2024-01-05 becomes a real date cell with Excel’s default date format, TRUE and FALSE become logical values, and 50% becomes 0.5. Values that could change on the way stay text cells instead: numbers that start with 0 or +, such as 00123 or a phone number; whole numbers of 16 digits or more, which Excel could only keep to 15; short pairs such as 1-2 or 3/4; and values whose meaning depends on the country, such as 1,234 or 01/02/2024, unless the same column (or, failing that, the file) has a value that settles it, such as 12.5 or 31/12/2024. That is how 1.234,56 in a semicolon-separated European or Latin American CSV becomes 1234.56. The preview shows the original CSV text, so check the types in the downloaded file.

How to use it

• Pick or drop a CSV, TSV or TXT file in the Upload file tab. For a table copied from an admin screen or an email, put it in the Paste text tab and press Load as table.
• Check the row and column count in the status line, and use the preview to confirm the columns split correctly.
• Press Download XLSX to save a .xlsx named after the original file. A pasted table is saved as sheetmoa.xlsx.
• Open it in Excel, check that number and date columns became real numbers and dates and whether any values were kept as text, and adjust cell formats if needed.

When it helps

Common snags

Tip The converted workbook has no filters, so click any cell in the header row in Excel and press Ctrl+Shift+L to switch filters on for every column at once.