Excel, calculate hh:mm time difference

I have 2 cells (A1, A2), formatted as [h]:mm for example:

Example 1
A
1 40:00
2 30:00
3 Here should display -10:00

In cell A3, I want the hours:minutes difference between the 2 cells, in the same format ([h]:mm). In the above example, in A3 it should display -10:00.

Example 2
A
1 40:00
2 45:00
3 Here should display 5:00

I have tried =TEXT(A1-A2, "[h]:mm") in A3 which works when A2 is smaller than A1, but in example 1 it will display 10:00 instead of -10:00 and in example 2, it will error.

How could I achieve that calculation?


Solution 1:

Add the - with the text format to have a "negative" time.

=TEXT(A1-A2,"-[h]:mm")

For both cases, use:

=IF(A1>A2,TEXT(A1-A2,"-[h]:mm"),A2-A1)