Convert CSV to Excel while preserving leading zeros and long IDs

Why does this happen?

CSV cannot declare a cell type. Spreadsheet software can interpret a code as a number, remove leading zeros, round long numbers or turn date-like text into a date. Text cells avoid those automatic type conversions.

Follow these steps

1. Choose the CSV from before any destructive spreadsheet save.
2. Review locations flagged for leading zeros, long integers and date/exponent-like patterns. These are risk indicators, not proof of existing damage.
3. Select Excel (.xlsx) — preserve every value as text. Formula-like values are written as strings, not formulas.

Fictional example

001 → text 001
12345678901234567 → text 12345678901234567
=1+1 → literal text, not a calculation

What this can and cannot do

Amounts are text too. Convert only the relevant columns to numbers when you need calculations. Already missing zeros or digits cannot be reconstructed. XLSX export rejects cells exceeding 32,767 characters; CSV remains an option.

Reopen the downloaded file and inspect the identifiers. Follow the receiving system’s import requirements before uploading elsewhere.