CSV to XLSX Converter

Free, no sign-up. Your files never leave your device.

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How to convert CSV to XLSX

  1. Click the box above or drag your CSV files onto it — you can add many at once.
  2. Wait a moment while your browser converts them. Nothing gets uploaded.
  3. Download each XLSX separately or grab them all in one ZIP file.

Why use this converter

  • Your files stay with you

    Conversion runs on your device. Documents are never uploaded, so nobody but you can see them.

  • No garbled text

    The encoding (UTF-8 or Windows-1251) and the delimiter (comma, semicolon or tab) are detected automatically.

  • Numbers stay numbers

    Numbers are numeric in the XLSX right away, while codes with leading zeros stay text.

  • Many files at once

    Add up to 100 files at a time and download the results as one ZIP.

Frequently asked questions

Why convert CSV to XLSX?

Excel opens CSV by its own rules: it may misread the encoding or delimiter, turn codes into numbers and drop leading zeros. An XLSX already has everything in columns and opens the same everywhere.

Which delimiter does it need?

Any: comma, semicolon or tab is detected from the file's contents. TSV works too.

What happens to numbers?

Numbers become real numbers you can calculate with. Values with leading zeros — codes, phone numbers, ZIP codes — stay text so the zeros aren't lost.

What if the text uses another encoding?

The encoding is detected automatically: UTF-8, UTF-16 or Windows-1251, which older Notepad versions and Excel in Cyrillic locales use.

What about dates?

Dates are carried over as text, exactly as written in the CSV, without converting them to another format.

Is it safe?

Yes. Only the converter itself is loaded from the site; your file is processed in your browser and never sent to a server.

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