CSV to Excel converter
Turn a CSV into a proper .xlsx workbook that opens cleanly in Excel, Numbers and Google Sheets, without the leading-zero and scientific-notation damage you get from opening the CSV directly.
Loading the tool…How to use it
- Paste CSV or drop one or more CSV files (each becomes a sheet).
- Choose whether numbers should be stored as numbers or everything kept as text.
- Download the .xlsx.
Private by design
The conversion runs as JavaScript in this tab. Your data is not uploaded, logged or stored. There is no account and no file-size paywall.
Protecting your data from Excel
When Excel opens a CSV it guesses types. 00501 becomes 501, a 16-digit card or order ID becomes 1.23457E+15 and loses its last digits (Excel keeps only 15 significant digits), and 3-4 becomes 3 April. This converter writes cells with explicit types: codes with leading zeros and numbers longer than 15 digits are stored as text, so they survive.
Several CSVs, one workbook
Drop several files and each becomes its own sheet, named after the file (trimmed to Excel’s 31-character limit).
Questions
Is my file uploaded anywhere?
No. The file is read by JavaScript in this tab and never leaves your device. You can load the page, switch off Wi-Fi and it keeps working.
Will formulas in my CSV work?
Cells starting with = are stored as text by default, which protects you from CSV formula injection. Untick the safety option to keep them as formulas.
Is there a row limit?
Excel sheets hold at most 1,048,576 rows. Bigger CSVs are split across extra sheets automatically.
Does it work for Google Sheets?
Yes. Upload the .xlsx to Drive, or import the CSV directly: Sheets handles CSV well.