Formatting date/time (merging two columns)

Hello all,

I have a spreadsheet with date data in one column and time data in the other.

Column A contains: mm/dd/yyyy
Column B contains hh:mm:ss

I would like to combine these two into a single column so that it is "mm/dd/yyyy hh:mm:ss"

The only way i've been able to do this thus far is to copy and paste the data into word, convert it to text with a space inbetween, and paste it back into excel. Given that these spreadsheets are upwards of 9000 rows this tends to crash word. I figured there must be an easier way to do it.

Thanks in advance!

Thanks, that was extremely helpful!