My ZIP+4ZIP codes are in separate columns. How do I merge them into 1?

All numbers of a ZIP code must be contained within 1 cell.

If using a ZIP+4ZIP code, use the following format: [5-digit ZIP code] - [+4ZIP]
For example: 90210-6808

• Click the cell where you want to put the first set of combined numbers.
• Type the combined zip code (example: 90210-6808).
• Press ENTER.
• Click Data.
• Click Flash Fill from the Data Tools group.
• Excel automatically combines the remainder of the text for you.