Custom formula run in blanks for varying range sizes

Okay. I need to be able to calculate the difference between the last day and first day of a job so that the first day is included in the calculation. I have been entering the same formula manually by hand for each range.

The tricky part (for me at least) is that I need a macro that will find the blank spaces and automatically apply the above formula to the correct range of data until it reaches the end of the sheet for both columns.

Each sheet I am working with has about 30 different ranges there are approximately 30 sheets to do this for. I think I would be bald if I tried to do this all manually.

Any direction at all will be GREATLY appreciated.

Days Days Plus Breaks

36 60
37 61
38 62
39 63
40 64
41 67
42 68
43 69
44 70
45 71
46 74
47 75
48 76
49 77
Blank Blank <-----this is where i would want the 77-60+1 to calculate
4 41
5 42
6 43
7 44
8 45
9 48
10 49
11 50
12 51
Blank Blank <-----this is where i would want the 51-41+1 to calculate
1 1
2 4
3 5
4 6
5 7
Blank Blank
1 1
Blank Blank
3 73
4 74
5 77
6 78
7 79
8 80
9 81
Blank Blank
1 1
2 2
3 3