Category is the list on the left on the Number tab.

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__________________________________
HTH

Bob

"jacsdad" wrote in message
...
In Excel 2007, I am attempting to calculate the difference between two
times.
I have read the instructions in Help and found what I need to do, but
cannot
fine where to format the Category to Customize to: [h]:mm.

On the Home tab, in the Cells group, click Format, and then click Format
Cells.
In the Format Cells dialog box, click the Number tab.
Under Category, click Custom.
In the Type box, type [h]:mm.

Thanks ahead of time...
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jacsdad