spreadsheet → spreadsheet
Convert CSV to XLSX
Convert CSV to XLSX in seconds. Free, no signup, no watermark, no file-size limit. Your file is processed in your browser and never uploaded.
At a glance
- Source
- CSV
- Target
- XLSX
- Where it runs
- Your browser
- Cost
- Free, unlimited
- Account
- Not needed
Converter
CSV to XLSX
Drop one or more comma separated values files.
or select comma separated values
Your file never leaves this browser
The details
What happens when you convert text into a spreadsheet
One table, one row per line, values separated by commas. The most importable format there is. The text is parsed as a table — rows split on newlines, columns on the delimiter — and written into a worksheet with a header row. The result is a microsoft excel's modern spreadsheet. a workbook of sheets, formulas and formatting, produced entirely inside your browser.
What survives
- Every value, in its own cell
- The row and column structure
What changes
- The file becomes a binary workbook, so it is no longer readable in a text editor
- Values that look like numbers become numbers, and the rest become text
Where it goes wrong
- A leading zero in an account number is often turned into a number and the zero disappears
- Very long text in a cell may be truncated by the spreadsheet format
Why anyone would do this
Somebody is always asking for the list as a table, and nobody wants to do it by hand.
About the format
One table, one row per line, values separated by commas.
Plain text. Each line is a record, each value is separated by a delimiter, and the first line is usually a header row.
- Where it is good
- Almost every system on earth can import it
- Plain text, so you can read and edit it directly
- Perfectly suited to genuine tables
- Where it falls short
- No formatting, no multiple sheets, no formulas
- Commas and newlines inside values need careful quoting
- Encoding problems appear the moment a spreadsheet exports it
- You will find it on
- Data analysts, developers, every import button ever built
The thing people miss
A CSV exported by Excel on Windows is often UTF-8 with a byte order mark, which makes the first column name read as "Name".
About the target
Microsoft Excel's modern spreadsheet.
A ZIP archive of XML worksheets, a shared string table, styles and the formula definitions for each cell.
- Full formulas, formatting, charts and multiple sheets
- Opens in Excel, Google Sheets, LibreOffice and Numbers
- Data validation and conditional formatting survive
Real jobs
What people are actually doing with CSV
Getting data out of a system that only exports plain text
Importing a list into a website, a CRM or a bank portal
Turning a spreadsheet into something a script can read
Specification
The details, in one table
| Source format | CSV — Comma separated values |
|---|---|
| Target format | XLSX — Excel workbook |
| Typical source size | 1 KB – 100 MB |
| Runs | In your browser |
| Account needed | No |
| Watermark | None |
| File extension | .csv → .xlsx |
How to
CSV to XLSX, step by step
- 01
Add your comma separated values
Drag the file onto the drop zone, or tap to browse. Only one file is needed.
- 02
Choose the XLSX settings
Set the XLSX-specific options — everything happens locally, so the speed is your device, not a queue.
- 03
Download the result
The finished XLSX downloads to your device. Nothing is uploaded and nothing is retained.
Also available
CSV converts into
Questions
CSV conversion questions
What actually happens to my CSV file when I convert it to XLSX?
The text is parsed as a table — rows split on newlines, columns on the delimiter — and written into a worksheet with a header row. So the CSV file is unpacked, the content is laid out, and the result is written out as XLSX. Every value, in its own cell survives unchanged.
Will converting CSV to XLSX reduce the quality?
For this particular conversion, not in the way you would expect. Every value, in its own cell — the CSV content is not re-encoded in a lossy way. The only thing that changes is the format it is stored in.
Is my CSV file uploaded to a server?
No. This CSV to XLSX conversion runs as JavaScript inside your browser tab. The file is read from your device and the result is written back to your device, so there is no upload step, no file-size limit and no copy of your CSV file on any server.
Do I need an account or will there be a watermark?
Neither. There is no sign-up step, no email capture and no watermark on the output. The only limits are the ones your own device imposes.
What is the most common mistake people make when converting CSV to XLSX?
A leading zero in an account number is often turned into a number and the zero disappears
Why would somebody convert CSV to XLSX at all?
Somebody is always asking for the list as a table, and nobody wants to do it by hand. In short: getting data out of a system that only exports plain text
Something most people do not know about CSV?
A CSV exported by Excel on Windows is often UTF-8 with a byte order mark, which makes the first column name read as "Name".