CSV and XLSX — what is the difference
A CSV file is plain text: just values separated by commas, with no formatting, no sheets and no formulas. An Excel .xlsx file is a real workbook with columns, styles, multiple sheets and formulas. Converting gives you a file you can format, filter and share as a proper spreadsheet.
What happens when you convert
The tool detects the separator automatically — comma, semicolon, tab or pipe — handles quoted values, and writes every value into its own cell of an .xlsx file. The first row is styled as the header and column widths are adjusted to fit the content.
Why values are kept as text
Every value is stored exactly as it appears in the CSV, as text. This protects phone numbers, PIN codes, account numbers, product codes and IDs with leading zeros from being changed — opening a CSV directly in Excel often turns 0091234 into 91234 or long numbers into 1.23E+15. When you want to calculate, select the number columns and use Convert to Number.
Common problems and how to fix them
SUM gives 0: the cells are text — use the green warning triangle → Convert to Number. Accented or Indian-language text looks wrong: the CSV was not UTF-8; export it again as UTF-8. All data is in one column: the separator was unusual — check the file in a text editor.
Good habits
Keep the original CSV export, convert number columns deliberately, and save formatted reports as .xlsx for sharing.