A CSV stores text separated by delimiters. It does not declare whether a value such as 00127 is a number or an identifier. Spreadsheet software may interpret it as the number 127 when opening the CSV.

Write identifiers as text cells

FileToast’s CSV to Excel tool writes cells as text in an XLSX workbook. That preserves leading zeros and long identifiers. It also means numeric-looking cells may need to be converted to numbers before you calculate totals.

Check a representative sample

Open the downloaded workbook and inspect postal codes, long IDs, dates, and values beginning with a plus sign. Keep a copy of the source file. Avoid converting identifier columns to numbers.

Understand the reverse conversion

Excel to CSV exports values from one worksheet. CSV cannot preserve formatting, multiple worksheets, or cell types. FileToast does not calculate spreadsheet formulas; cached formula results are exported when available.

CSV exports escape formula-like values to reduce the risk of spreadsheet formula execution. This can add a leading apostrophe to those values.