Count number of revenue months until cost is covered

[macrorookie]

Hello - I cannot figure out how to write the correct formula for my problem.

I attached a sample file.

I want to show how many months of cumulative revenue it takes to cover my cost.

In the attached example, I know that in month #8 I have covered my $2,000 cost ($2,159 total income), so I wish "8" to show as my answer.

Thanks in advance for any help.

[MarvinP]

Hi macrorookie,

How about using a helper column with a running total and then a match formula. See the attached. Change the amount and see the month change.

Match in Running Total.xlsx

[macrorookie]

That will work perfectly! Thank you, MarvinP.