How to Convert CSV to XLSX
Learn the easiest ways to turn a CSV file into an Excel spreadsheet.
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CSV to XLSX
Turn CSV files into Excel spreadsheets in seconds. The delimiter is detected automatically, numbers are converted, and columns are sized to fit. Everything happens in your browser.
No registration required
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Works on any device
Quoted values, commas inside quotes and line breaks inside cells are handled correctly. Numbers with leading zeros (such as ZIP codes or IDs) and very long numbers stay as text so nothing is changed. UTF-8, UTF-16 and Windows-1252 files are read automatically, so all languages are supported.
Your XLSX files are ready
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Your CSV files are converted in your browser — nothing is uploaded.
Instant
Files convert on your device, with no waiting for uploads.
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No account and no limits on how often you use it.
How to convert CSV to XLSX
Three quick steps. Nothing to install and nothing leaves your device.
1
Add your CSV files
Click the upload area or drag one or more .csv files onto it.
2
Choose settings
Keep auto-detect, or pick the delimiter, number handling and column width.
3
Convert and download
Press Convert, then download each XLSX file or all of them as a ZIP.
Learn about Spreadsheets
Helpful guides about CSV and XLSX files.
Frequently asked questions
Quick answers about the ConvertKit Lite CSV to XLSX tool.
Are my files uploaded to a server?
No. The XLSX file is created in your browser, so your CSV files stay on your device.
How is the delimiter detected?
The tool checks the first lines of the file for commas, semicolons, tabs and pipes, and picks the one that appears consistently on every line. If it guesses wrong, choose the delimiter yourself from the list.
Why did my ZIP codes or IDs keep their leading zeros?
Values such as 00123 and numbers longer than 15 digits are kept as text on purpose. Excel would otherwise remove the zeros or round the number. Choose "Keep everything as text" if you want every cell left exactly as written.
Does it support Bengali, Arabic, Hindi or Chinese text?
Yes. XLSX files store Unicode text, so every language is kept as real, selectable text. The tool reads UTF-8, UTF-16 and Windows-1252 CSV files automatically.
Are dates converted?
Dates are left as text exactly as they appear in the CSV, so day/month order is never guessed wrongly. You can format them as dates in Excel afterwards.
Are there size limits?
Each file can be up to 20 MB. An Excel sheet holds at most 1,048,576 rows and 16,384 columns, and a single cell holds up to 32,767 characters. Longer cells are shortened.
Can I convert many files at once?
Yes. Add several CSV files, convert them together, and download each XLSX file or one ZIP.