CSV to XLSX Converter

A CSV file is plain text: one record per line, values separated by a character, usually a comma. Every spreadsheet can open one, which is why banks, online shops, payroll services and databases export them. But opening a CSV is a guess. The spreadsheet has to decide which character separates the columns, which text encoding the file uses and what type each value is, and it often decides wrong.

The results are familiar: a whole file packed into column A because it uses semicolons, names with accents turned into strings of odd symbols, long account numbers shown in scientific notation. Converting the CSV into a real .xlsx workbook settles the delimiter and encoding once, so the person you send it to opens a sheet that already has columns, rather than a text file their spreadsheet has to interpret.

A workbook can also do what a CSV cannot. Once the data is in .xlsx, you can add formulas, formatting, filters, charts and more sheets, and save all of that in the same file.

CSV files have no row limit of their own; a database export can run to millions of lines. An Excel worksheet does have one, set by Microsoft and shown below. A CSV with more lines than that cannot fit on one sheet, and Excel itself warns when it opens such a file and drops the rest.

Most exports are far smaller, but large logs, transaction histories and analytics dumps can exceed it. If yours does, split the CSV into parts first, or load it into a database or a tool built for large data rather than a spreadsheet.

The CSV format is less standard than its name suggests. RFC 4180 describes commas between fields and double quotes around any value that contains a comma, a quote or a line break, but many programs write their own variants. Countries that use the comma as a decimal mark often export with semicolons; database tools like tabs; some systems use pipes. Auto detect looks at the file and picks the separator it actually uses, and you can set it by hand under Advanced settings if a file is unusual.

Encoding is the other trap. A file saved as UTF-8 keeps every language intact, while an older export may use a regional code page. If names come out wrong, choose the matching Text encoding and convert again; the workbook then stores the text correctly for good.

Exports often carry invisible problems, such as spaces after a product code or before a surname, which make lookups and filters fail later. This page has Trim spaces switched on, so those are removed from the start and end of every value during conversion. Dates can be left as they are or rewritten in one format under Dates, which helps when a file mixes day-first and month-first dates.

For other directions, the Data Converter turns spreadsheets into CSV, JSON, XML or SQL, and an Excel file can become a printable PDF with XLSX to PDF. Contact exports from phones arrive as vCard files, which VCF to CSV turns into rows; for a quick table from a web page, use HTML to XLSX.

The sheet in each new workbook is called Sheet1 unless you type another name under Sheet name, up to 31 characters. Naming it after the export, such as the month or the account, makes the file easier to recognize once several workbooks are open side by side.