Hello Friends,

Please see example file attached example sum until true.xlsx

Suppose we have this data:

Number1 Number2 Number3 Condition
0 0 0 TRUE
0 0 0 FALSE
0 0 0 TRUE
1 0 0 FALSE
0 0 0 TRUE
1 0 0 FALSE
1 0 0 FALSE
0 0 0 TRUE
1 0 0 FALSE
1 0 0 FALSE
0 0 0 TRUE
0 0 0 FALSE
1 0 0 FALSE
0 0 0 TRUE
1 0 0 TRUE

In additional column I need to sum up range of data, but only until next TRUE CONDITION. IT SHOULD LOOK LIKE THIS:

0 0 0 TRUE 0
0 0 0 FALSE
0 0 0 TRUE 1
1 0 0 FALSE
0 0 0 TRUE 1
1 0 0 FALSE
1 0 0 FALSE
0 0 0 TRUE 2
1 0 0 FALSE
1 0 0 FALSE
0 0 0 TRUE 1
0 0 0 FALSE
1 0 0 FALSE
0 0 0 TRUE 0
1 0 0 TRUE 1

I can't figure out a clever way using functions to do it. I hope You will understand, even if I can't explain it very properly.