Tool · Spreadsheets
CSV → Excel without garbled text or lost zeros
Excel opens many CSV files as gibberish and turns 00123 into 123 and long ID numbers into 1.23E+17. MSGView detects the encoding and the delimiter, keeps zeros and long numbers as text, and makes a real .xlsx — in your browser, without uploading the file.
Drag a .csv or .txt file here
One file or several. Up to 200 MB, read piece by piece.
The example opens a built-in Shift-JIS file, so you can see the result without a file of your own.
.csv · .tsv · .txt — UTF-8, UTF-16, Shift-JIS (CP932), EUC-KR, GB18030, Big5, Windows-1251/1252
Convert CSV to Excel in 3 steps
- Drop the CSV Drag the file onto the page or choose it. The first 20 rows appear at once, already readable.
- Check the encoding and delimiter Both are detected automatically and can be changed. Columns that Excel would damage are marked blue: they are kept as text.
- Download .xlsx Press Download .xlsx. Or save a CSV in UTF-8 with a BOM, which Excel opens correctly by double-click.
Why does Excel show garbled text?
A CSV file does not say which encoding it uses. Excel guesses, often wrongly: a Japanese file saved in Shift-JIS, or a European one in Windows-1252, then opens as gibberish. MSGView reads the bytes and picks the encoding that decodes cleanly.
Leading zeros, long numbers, dates
Postal codes, customer numbers and phone numbers lose their leading zeros in Excel, and numbers longer than 15 digits are rounded. With “Keep leading zeros and long numbers as text” on (the default), these cells go into the .xlsx as text, exactly as in the file. Dates are not reinterpreted either.
Protection against formula injection
A cell that starts with = + − or @ can run as a formula when the file is opened in Excel. MSGView always writes such cells as text, so a downloaded CSV cannot run anything on your computer.
Questions
Is my file uploaded?
No. The CSV is read in your browser's memory and the .xlsx is created on your device. You can check in the Network tab of your browser's developer tools.
How large can the file be?
Up to 200 MB. Excel holds 1,048,576 rows per sheet; longer files continue on the next sheet.
Can I keep the CSV format?
Yes: “CSV in UTF-8 for Excel” saves a CSV with a byte-order mark, which Excel opens without garbled text.
Does it work on a Mac or a phone?
Yes, in any modern browser. Nothing is installed.