CSV to XLSX
Convert a UTF-8 CSV file into an Excel XLSX workbook with one worksheet. Values are imported as text to keep leading zeros, long IDs and date-like strings intact. Convert the columns you need to numbers or dates in Excel afterward.
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Accepts: text/csv, .csv · Max 1GB · always free
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Choose your .CSV file to convert it to XLSX.
Fast & Free
Convert files up to 1GB free with no account. Processing limits depend on the format and file contents.
Secure
Uploads use TLS encryption. Supported image conversions can run in your browser.
Check Your Result
Quality, transparency, and supported features depend on the output format. Keep your original file.
How to convert .CSV file to XLSX
Upload Your File
Choose your .CSV file using the upload area. The maximum file size is 1GB; processing also depends on your device and the file's contents.
Check the Output Format
The target format is .XLSX. Click Convert Now to start.
Download Your File
Download your .XLSX file, open it to check the result, and keep your original.
About CSV to XLSX
Content reviewed:
Keep IDs and dates from changing
A value such as 00123 stays 00123 instead of becoming 123. Long account or product IDs keep their digits, and 2026-10-14 stays the original text rather than being interpreted as a date. Amounts such as 12.50 are also text. Select and convert the appropriate columns to numbers in your spreadsheet editor before calculating totals.
Prepare the CSV encoding and separator
Export your source file as UTF-8 CSV. A UTF-8 byte-order mark is accepted. The converter detects common comma, semicolon and tab separators, and supports an explicit sep= declaration on the first line. Keep fields containing separators or line breaks inside double quotes. Ambiguous files may need re-exporting as standard comma-separated CSV.
What the workbook includes
The result contains one worksheet named Data. CSV does not store multiple sheets, charts, cell colors or workbook formatting, so conversion cannot recover them. Formula-like values beginning with an equals sign are kept as literal text rather than executed as formulas.
Check the result before using it
Compare the column headings, row count, accented characters and several IDs with the original CSV. If columns are misplaced, check the separator and quotation marks in the source export. Unsupported encodings and malformed files may fail; re-export as UTF-8 CSV. Excel worksheet and cell-size limits still apply.
Common reasons to convert .CSV file to XLSX
- Move a UTF-8 data export into an Excel workbook without losing ID zeros.
- Organize a semicolon-delimited export into spreadsheet columns.
- Review a CSV dataset as text before choosing number and date formats.
Frequently Asked Questions
Will leading zeros and long numbers survive conversion?
Values are written as text, so IDs such as 00123 and long digit strings are not automatically changed into numbers. If zeros were already lost in the source CSV, conversion cannot restore them.
Why do amounts appear as text in Excel?
This prevents automatic changes to IDs, dates and decimal text. Use your spreadsheet editor to convert the amount columns to numbers before using them in calculations.
Does it support semicolon-separated CSV files?
Common semicolon, comma and tab separators are detected. For ambiguous exports, use an explicit separator declaration or re-export as standard comma-separated CSV. Always check the resulting columns.
Are CSV formulas run during conversion?
No. Formula-like fields are stored as literal text. Add or enable any intended formulas yourself in your spreadsheet editor after reviewing the workbook.
Does renaming a CSV to XLSX do the same thing?
No. XLSX is a workbook format, not a different filename for CSV text. This converter creates an actual XLSX workbook that compatible spreadsheet applications can open.