Cumulative sum with data in unequal increments

[Chris88kemp]

Dear All,

I would like to calculate the cumulative volume of liquid from a pipe over the period of 22 years. Data has been given on a daily basis, however in some instances this covers multiple days.

The format of the native data is as follows:


[TABLE="class: grid, width: 500"]
<tbody>[TR]
[TD]DAY[/TD]
[TD]LIQUID RATE, M3/D[/TD]
[TD]CUMULATIVE VOLUME, M3[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]202[/TD]
[TD]= 202[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]210[/TD]
[TD]= 210 + 202[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]215[/TD]
[TD]= 215 + 210 + 202[/TD]
[/TR]
[TR]
[TD]13[/TD]
[TD]280[/TD]
[TD]= 280 + (215 * (13 - 3)) + 210 + 202
[/TD]
[/TR]
[TR]
[TD]30[/TD]
[TD]330[/TD]
[TD]= 330 + (280 * (30 - 13))+ (215 * (13 - 3)) + 210 + 202[/TD]
[/TR]
[TR]
[TD]etc[/TD]
[TD]etc[/TD]
[TD]etc[/TD]
[/TR]
</tbody>[/TABLE]

The issue starts on day 3 where the daily flowrate of 215 continues through to day 13, which then increases to 280 per day until day 30.

Does anyone know how this can be neatly calculated in a formula which I can replicate down. The data has 10,000 + rows so adding intermediate rows to cover each individual days is impractical.

Thanks in advance

 

[Fluff]

How about

Book1
	A	B	C
1	DAY	LIQUID RATE, M3/D	CUMULATIVE VOLUME, M3
2	1	202	202
3	2	210	412
4	3	215	627
5	13	280	2842
6	30	330	7652
Planner

Cell Formulas
Range	Formula
C2	=B2
C3	=B2*(A3-A2-1)+B3+C2