Cumulative Addition with constraint

[JoeChanps]

Col.H	Col. L	Col. O	Date:	14.09.2018
Date	Length	Cum. Length / Result
21.08.2018	4	4
25.10.2018	6	6
06.11.2018	8	14
29.11.2018	5	19
17.07.2018	9	13
01.08.2018	7	20
09.08.2018	12	32
22.08.2018	22	54

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Hey guys,

I need some help with a tricky problem and I have no clue how to solve it. Basically what I want is to accumulate the data with a constraint. So..
In Col. O are the results. Don't know if it's possible withou VBA?!

Every date that is before/equal 14.09.2018 should be accumulated (here the accum. dates are: 21.08.2018, 17.07.2018, 01.08.2018, 09.08.2018 and 22.08.2018).

And the other ones should be accumulated as well.

Thank you for your help.

With best regards
Joe

 

[Peter_SSs]

Like this?

Excel Workbook
	H	I	J	K	L	M	N	O	P	Q
1	Date				Length			Cum. Length / Result	Date:	14/09/2018
2	21/08/2018				4			4
3	25/10/2018				6			6
4	6/11/2018				8			14
5	29/11/2018				5			19
6	17/07/2018				9			13
7	1/08/2018				7			20
8	9/08/2018				12			32
9	22/08/2018				22			54
Cumulative length

 

[JoeChanps]

thx. i love you.

 

[Peter_SSs]

thx.

You're very welcome.

Just realised we could write the formula more simply though.

Excel Workbook
	H	I	J	K	L	M	N	O	P	Q
1	Date				Length			Cum. Length / Result	Date:	14/09/2018
2	21/08/2018				4			4
3	25/10/2018				6			6
4	6/11/2018				8			14
5	29/11/2018				5			19
6	17/07/2018				9			13
7	1/08/2018				7			20
8	9/08/2018				12			32
9	22/08/2018				22			54
Cumulative length

 

[JoeChanps]

Even better. I just have to understand the formula now, i.e. how it works. But you helped me a lot. I really appreciate it.