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CSV to Excel
Leading zeros, dates and long numbers kept as text where Excel would mangle them.
More free conversions, where you upload. The Fylane extension does the same work inside any upload form, on its own free share every day.Add to Chrome
How to convert CSV to Excel
- Drop the file.
- Nothing to choose.
- Press Convert and download.
What happens to your file
LibreOffice Calc reads the CSV (comma or tab, quoted fields, UTF-8) on Fylane’s servers and writes an XLSX with one sheet and one cell per value. Numbers and dates are recognised as Calc would recognise them; text stays text.
A CSV with a semicolon or another separator is read as best as it can be; the result says so if columns did not split.
Questions
Why does Excel break my CSV but this does not?
Excel guesses the encoding and the separator from your computer’s locale, which is why the same file opens cleanly on one machine and as one long column on another. This page reads UTF-8 and the standard comma, quotes included, and writes a real workbook — so by the time Excel sees it there is nothing left to guess.
Why did my CSV open as one column?
Because Excel expected a different separator. In much of Europe the list separator is a semicolon, so a comma-separated file arrives unsplit. Converting here sidesteps it: the columns are already columns in the .xlsx.
Are my long numbers safe?
This is the reason to convert rather than open. Excel mangles a CSV on sight — a leading zero on a postcode disappears, a sixteen-digit card or account number rounds off in the last digits, and 1-2 becomes a date. Values are written into cells here as what they are, so Excel never gets the chance to reinterpret them.
What about accented characters and other alphabets?
UTF-8 is read properly, so names and non-Latin scripts arrive intact rather than as the mojibake Excel produces when it assumes the wrong encoding.
Can it handle a semicolon or tab separated file?
Tabs and commas are handled directly. Another separator is read as best it can be, and the result tells you plainly if the columns did not split rather than handing you a one-column sheet without comment.
How big a file can I convert?
Comfortably into the hundreds of thousands of rows. XLSX itself stops at 1,048,576 rows per sheet, which is the format’s limit rather than this page’s.
Do it once, not on every form
Fixing a file here means downloading it and going back to the form. The Fylane extension does this work inside the form instead, on the file you already have.
And it keeps the result. The next application that asks for a résumé, a cover letter and a photo fills all three from one tap, each one refitted to what that site accepts.
Your files stay in the browser, encrypted, on your machine. Nothing is uploaded to keep them and nothing is sent anywhere to fill a form.
Related tools
Do this in code
curl -X POST https://api.fylane.dev/v1/jobs \
-H "Authorization: Bearer $FYLANE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"file_id": "<file id>",
"operation": "convert",
"options": {
"to": "xlsx"
}
}'The same operation, convert — Documents into another document format: Office, text and HTML to PDF by default, or by `to` into docx, odt, rtf, txt, html, xlsx, ods, csv, pptx, odp, md or epub (Markdown and EPUB through pandoc). Images to WebP. Upload first with the quickstart; every option is on the operations page. 500 free credits a month, then $5 per thousand.