Zip codes lost the zero — how to save Excel to CSV without losing leading zeros
Want to save an Excel column of zip codes to CSV without the leading zero disappearing? The fix has to happen before you save — once the cell is a number, the zero is already gone. Here's the exact sequence that keeps it
The save step can't fix what's already broken
Save As CSV writes out exactly what's already in the cells — it doesn't inspect the data or apply any judgment about zip codes specifically. If the leading zero was already dropped when the value was typed or imported as a number, the export step has nothing left to preserve; the fix has to happen upstream of the save, not during it.
Preparing the column before you type or import
Select the destination column and set Format Cells to Text before entering any zip codes, so each one is stored as a literal string of characters rather than being interpreted as a number. The custom format 00000 is a workable alternative for standard five-digit zip codes, padding a stored number back out to five digits for display and for export, but it breaks down for a ZIP+4 code with a dash in it, where Text format is the safer general-purpose choice.
If you're re-importing from another CSV first
Use Data > Get Data / From Text rather than double-clicking the file to open it — the wizard lets you set the zip code column's type to Text explicitly, so Excel's automatic type detection never gets a chance to convert it to a number. Re-save to CSV only after confirming, by checking left-alignment in the cells, that the column genuinely holds text.