how to understand number custom format

[lezawang]

Hi
I want to understand these codes under number custom formatting. For example what does #,##0;-#,##0 mean or what does #,##0.00;[Red]-#,##0.00 mean.

Is there any website/video explain step by steps what these codes mean and how you can created your own.
I have seen some video/articles about this but no one really explain for example why they put 2 ## and what they put 0 in ##0 and what does #,##0 mean.. and why not ###,##0 instead.

I am sure there is a syntax or format to use these symbols to create rule or number formatting. Any help would be very much appreciate it. Thank you.

 

[shg]

You probably entered 1.5 into that cell

12AM Ford; 1, not 1.5.

 

[FDibbins]

oops missed that, thx, shg