CSV to Excel Converter

What this handles that a double-click does not

• Leading zeros survive. A postcode 01000 or a product code 00123 stays text instead of becoming 1000 and 123.
• Long numbers stay intact. Excel keeps only 15 significant digits, so a 16-digit card number or a long order id comes back corrupted. Anything that long is written as text.
• Semicolons and commas. The separator is detected by which one gives a consistent column count — a file of Surname, First name pairs separated by semicolons is not mistaken for a comma file.
• European numbers. Set the decimal to a comma and the thousands separator is read whichever it is — a space, a dot, or the narrow space Excel itself emits: 1 234,56, 1.234,56 and 1 234,56 all become the number 1234.56. The Swiss 1'234.56 works too.
• UTF-8 accents. The file is read as UTF-8 and the byte-order mark is stripped, so café does not arrive as café.
• Quoted fields. Separators, doubled quotes and line breaks inside a quoted field are all read correctly, per RFC 4180.
• Text that looks like a formula. A cell containing =1+1 is written as text, not as a formula.
• Whole columns stay consistent. If one code in a column had to stay text, the entire column does, so it sorts and filters as one kind of thing.

Is my file uploaded anywhere?

No. This page has no server side: the file is read and written back by JavaScript running on your own machine. You can check it by opening the page, disconnecting from the network, and converting a file anyway.

The equivalent in Excel and Google Sheets

To do the same by hand in Excel, use Data → From Text/CSV rather than double-clicking, then set each problem column to Text in the import preview. In Google Sheets, use File → Import and switch off Convert text to numbers, dates and formulas to keep codes intact.