Online tools
CSV to Excel converter (free, no upload)
A free Duaer tool that turns CSV into .xlsx in your browser. It detects UTF-8 or GBK, keeps long IDs as text, and never uploads the file.
How to use it
- Drop the file into the box above, or click "choose a file".
- Check the preview to make sure rows and columns line up.
- Click "Download .xlsx".
- Pick several CSV files at once to get one .xlsx with a sheet per file.
Conversion rules
- Encoding: UTF-8 first, then GBK if UTF-8 fails. CSV exported from older Excel or many Chinese business systems is GBK.
- Delimiter: comma, tab, semicolon, or pipe, detected automatically.
- Numbers: plain numbers become numeric cells you can sum. Codes with a leading zero and numbers longer than 15 digits (national IDs, card numbers, order numbers) stay text.
- To keep every cell as text, tick "Write every cell as text".
Automate it in Duaer
Converting the same CSV every day? In Duaer, read it with Extract from File › Extract From CSV, then write it with Convert to File › Convert to XLSX. For GBK files, use Extract From Text File (Options › File Encoding: gbk) and split rows as in Parse CSV in a Code node.
Questions
Why does Excel show garbled text for my CSV?
Excel often opens UTF-8 CSV with the system code page. Convert it to .xlsx with the Duaer CSV to Excel tool and the encoding problem goes away.
Why do long IDs turn into 1.10101E+17?
Excel cuts numbers past 15 digits. The Duaer converter keeps longer numbers as text, so the .xlsx shows the full value.
Is there a file size limit?
Duaer sets no limit; your browser memory does. CSV files of tens of megabytes usually work.
In this section
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