Summarising variable weekly payments to months

Hi guys,

It's rare I come to an excel help forum as I try and work things out for myself but alas, I'm stumped on the best way to achieve this.

I have varying weekly interest, say 100 in week 1, 200 in week 2, 300 in week 3 etc and I'm simply trying to calculate the exact interest in the month. As the some weekly interest relate over two months, I'll have to pro rate to get the exact figure.

Is there an elegant solution to this - my thoughts are utilising MINs and MAXs here. Can't seem to attach at the moment, but an example of what I'm trying to get to is provided below.

Thanks!

Example.PNG

Hello,

So you want to sum the values between G1 and G2? if so, put this in G3:

Formula:

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and don't forget to press ctrl+shift+enter

That's not what he's trying to do as 27.04 is included into the calculation due to the fact that the next payment starts on 04.05. But what I don't understand is how he arived at 836 for the second calculation

I don't think the 836 has anything to do with the calculation. But if he wants the whole month:

Formula:

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*CTRL+SHIFT+ENTER

Cheers!

This will calculate the totals in month based on a helper column:

Formula:

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I am not sure if is possible without a helper column, at least not for my skills. cause you need to calculate based on days from weeks dates instead of using month