# How many days to interest compound goal

I usually use this google sheets formula to calculate the compound interest, for 30 days. B2*((1+B3/100)^30)
B2=invested amount
B3=daily percentage

I would like to have a formula to calculate how many days I would have to wait to gain a specific amount.

I would fill : invested amount, daily percentage, and goal amount and the formula will calculate how many days is needed to achieve this.

Is it possible to have this?

Hope I explained it well, english is not my natural language

For the sake of clarity, let's assume that in addition to entering the present value (i.e., "invested amount") in B2 and the daily interest in B3, you will also enter into B4 the target future value.

This formula should tell you how many days it will take to reach that target future value:

`=ROUND(NPER(B3,0,-1*B2,B4))`

`NPER` is the "`N`umber of `PER`iods" function.

The second parameter (currently set to `0`) is the amount of any additional regular payments you will make into the investment per period (in your case per day, which is zero).

The present value must be multiplied by `-1` in the formula, because as far as accounting goes, you are paying that amount up front, not earning/gaining it.

`ROUND` is used simply to eliminate partial periods, which, being days, are irrelevant.

• Hi, Thanks for your answer, I tried your formula, but I have an "formula analysis error". here is a link to my sheets : docs.google.com/spreadsheets/d/… . Thanks
– fred
Commented Jan 10, 2022 at 21:43
• and it's a invest so I will pay some money to receive interrests
– fred
Commented Jan 10, 2022 at 22:01
• My answer is correct. You entered your percentage as a whole number rather than a decimal amount, so it would need to be divided by 100. And you didn't multiply the present value by -1. See my newly added sheet "Erik Help." Commented Jan 10, 2022 at 22:30
• thanks a lot, it works
– fred
Commented Jan 10, 2022 at 22:44
• Great. Please take a moment to mark my solution as "Best Answer." This allows the volunteer contributors to see at a glance from the main listings page which issues have been fully resolved; and it helps future site visitors most quickly find answers that match their own searches. Commented Jan 10, 2022 at 23:01