A CSV file is wonderfully simple — plain text, values separated by commas — but the moment you need to sort, filter, format or share data with someone who lives in Excel, plain text stops being enough. This free CSV to XLSX converter turns your .csv file into a genuine Excel workbook in seconds. Drop the file in, check the preview, press convert, and download a .xlsx that opens cleanly in Excel, Google Sheets and LibreOffice.
How to convert a CSV file to XLSX
Drag your file into the box above, or click the box and choose it from your device. The tool reads the file and shows a preview of the first five rows, along with the total row count, so you can confirm you picked the right export before anything happens. Then press Convert to XLSX. The workbook downloads with the same base name as your CSV — sales.csv becomes sales.xlsx — ready to open, format and share.
What you get: a real workbook, not renamed text
The result is a true Office Open XML workbook, the native format of modern Excel, not a text file wearing an .xlsx disguise. The sheet mirrors the CSV rows exactly: every row and column lands in the cell it occupied in the text file, values with commas inside quotes stay together as single cells, and text in other languages and scripts is preserved. Once it is a workbook you can bold the top row, freeze panes, add filters, build charts and save without Excel warning you about the format on every close.
Delimiters, TSV files and headers
Not every “CSV” actually uses commas. Exports from many European tools use semicolons because commas are decimal marks there, and tab-separated files (.tsv) are common in data work. The reader sniffs the delimiter automatically, so comma, semicolon and tab files all convert without you changing any settings. One honest note about the first row: the sheet simply mirrors your CSV rows exactly as they are. If your first row holds column names, it becomes the first row of the sheet — ready for you to style as a header in Excel — and no row is ever silently treated as something it is not.
Your data never leaves your device
Spreadsheets often hold the data you least want on a stranger’s server: customer lists, invoices, grades, payroll. This converter therefore does all of its work on your own machine: the files are converted locally in your browser and never uploaded to any server. Nothing is transmitted, stored or logged, which also means the tool keeps working offline once the page has loaded.
Size limits and tips
Files up to 10 MB convert comfortably — that is roughly hundreds of thousands of ordinary rows. For the cleanest result, make sure each row has the same number of fields, keep quoted text properly closed, and save exports as UTF-8 so accented characters and other scripts arrive intact. If a number-like value such as a long product code must keep leading zeros, format those cells as text in Excel after converting, because spreadsheets otherwise treat them as numbers.
CSV to XLSX Converter – frequently asked questions
Is this CSV to XLSX converter free?
Yes. It is completely free, needs no sign-up, and you can convert as many files as you like, one at a time.
Will the XLSX file open in Excel and Google Sheets?
Yes. The output is a standard Excel workbook (.xlsx) that opens in Microsoft Excel, Google Sheets, LibreOffice Calc and Apple Numbers.
Is my CSV uploaded to a server?
No. The files are converted locally in your browser and never uploaded, so your data stays on your device from start to finish.
What is the largest CSV I can convert?
Up to 10 MB per file. Larger exports are best split into smaller files first, converted one by one, and combined in Excel if needed.
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