conditional formatting or custom formatting?

[lezawang]

Hi
If I want to format a cell so if the user enter number like -10000 then excel change it right away to -10,000 in Red color. Is that conditional formatting or custom formatting.

Also I have seen in custom formatting a code like this #,##0 what does the 0 mean here? and what i have 2 ## after the comma? why not ### or what is the difference. Thank you so much.

 

[Scott T]

Do you want to change all negative numbers? If so you can use custom formatting. If there are other conditions then use conditional formatting.
Be aware there are different section of the format

_($* #,##0.00_);_($* (#,##0.00);_($* "-"??_);_(@_)

When the number is positive; when the number is negative; when it is zero; when there is text
Note that if you leave a section with no format it will show as blank so

;[Red]-#,##0;

Would not show positive numbers in the cell, you could see the number in the formula bar and it is the cell you just don't see it. and negative number would be -7


The # is for optional display, if there is a number there display but if there is not do not display anything. So #,##0 would display 700 as 700 instead of 0,700(how it would display if you used 0,000). 0 is to display the digit even if empty (leading zeros).