Convert CSV to Excel (XLSX)

Convert CSV to Excel online. Get an .xlsx workbook with numbers stored as numbers and leading zeros kept. Commas, semicolons and tabs are detected.

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Why convert CSV to Excel?

A CSV is plain text. Excel opens it, but it guesses the separator and the encoding, turns long IDs into scientific notation, strips leading zeros from ZIP codes and phone numbers, and sometimes puts a whole row in one column. An .xlsx workbook has none of those problems. It opens the same way in Excel, Google Sheets, Numbers and LibreOffice, and you can add formatting, formulas and more sheets to it.

How to convert CSV to XLSX

Drop one or more CSV files above and press Convert all. Papa Parse reads each file and works out the separator, whether comma, semicolon, tab or pipe. SheetJS then writes a compressed .xlsx with one worksheet named after the file. Download each workbook or all of them as a ZIP. The CSV is read as UTF-8, so accented letters and other scripts come through correctly.

How values are stored

Each cell is checked before it is written:

Plain numbers such as 42, -7 or 3.14 become numeric cells, so you can sum and sort them.
Values with leading zeros, such as 00123, stay text so the zeros are kept.
Numbers longer than 15 digits, such as card or account IDs, stay text, because Excel would round them.
Everything else, including dates, percentages and numbers written with thousands separators, is stored as text exactly as it appears in the CSV.

Before you start

Input: CSV, TSV, and TXT. Output: XLSX. The settings appear before anything runs, so you can check them first. Your original file is never changed.

A valid file can still hold the wrong data. Before you import the result, check the row count, field names, text encoding, dates, IDs and a few unusual rows.

Keep the original until you have opened and checked the result. The work happens in this browser tab, so the size you can handle depends on your device's memory, your browser and the file itself.