RunToolRunCSV to Excel
Convert CSV files to Excel format.
How to Convert CSV to Excel
Select a CSV file
Click the upload area or drop the .csv you want as a spreadsheet.
Parsing happens locally
Rows and columns are parsed — including quoted fields and separators — and written into a real .xlsx workbook.
Download the Excel file
Open the .xlsx in Excel, Google Sheets or LibreOffice with proper columns.
The problem this solves
Opening a CSV by double-clicking hands it to Excel with whatever assumptions the system locale supplies. If those assumptions are wrong — the wrong separator, the wrong encoding — the file arrives mangled, and the usual response is to fix it by hand rather than to fix the import.
Converting deliberately means the separator and encoding are handled before Excel sees the data, so the workbook opens correct the first time.
Excel's autocorrect is the real hazard
Excel interprets values as it reads them, and its interpretations are aggressive. Leading zeros are stripped from postal codes and identifiers. Long numeric codes become scientific notation. Strings that resemble dates are converted to dates, irreversibly.
The gene-name case is the famous one — spreadsheet software converted certain gene symbols to dates so consistently that the naming committee renamed the genes. If that can happen to a scientific field, it can happen to your product codes.
Which columns need protecting
Anything that is an identifier rather than a quantity: postal codes, phone numbers, order references, barcodes, national ID numbers, account numbers. None of these are numbers in any meaningful sense — you never add two phone numbers — and all of them are damaged by being treated as such.
The rule that avoids the whole category is to decide the type of every column deliberately rather than letting the import guess. A column of identifiers is text, always.
Encoding and Turkish characters
A UTF-8 CSV opened by Excel without an encoding hint is often read as a legacy code page, which turns Turkish, Greek and Cyrillic characters into strings of replacement symbols. This is the single most common complaint about CSV files in non-English offices.
Producing a proper workbook rather than a CSV sidesteps it entirely, because the format stores its own encoding. The characters cannot be misread, since nothing is guessing.
What a workbook adds
Beyond correctness, the format gives you things CSV cannot carry: real column types, multiple sheets, frozen header rows, column widths that fit the content, and formatting that survives being sent to someone else.
For a file a colleague will actually work in rather than a program will parse, that is the difference between data and a usable document.
Checking, and privacy
After converting, look specifically at the columns you know are fragile — identifiers with leading zeros, long numbers, anything date-shaped. Scanning the first few rows is not enough, because the damage is often in a subset of values rather than the whole column.
Conversion runs in your browser, so exported customer lists and transaction records are not uploaded anywhere.