For formatting, right click a cell, select "Format Cells".
On the "Number Tab" select "Custom" from the "Category" list
Enter 000-000-000 as the format (in the text box below to the right)

For finding duplicates, you could use a a simple CountIf
EG.
Enter a list of phone numbers in Col A
Enter the function =COUNTIF($A$1:$A$500, A1) in B1
Copy B1 down as far as your list is long
If any cell in Col B is 1 then it is a duplicate.




"Sandeep Elbak" wrote in message ...
- How can I check (I need a formula) if a column contains same telephone number twice or not? It is too slow to check
manually (data / sort)

- How could I autoformat telephone numbers, like 040123456 = 040-123 456, so the numbers would be easier to read on
screen? I will not copy phone numbers to any other application, it is sufficient the numbers will be readable in
Excel, so no hard space bars are necessary.