# Formula to calculate value based on reverse percentage

1. ## Formula to calculate value based on reverse percentage

How do I create a formula to calculate a reverse value...for example, I can calculate Cell A3 by taking 10 (value in A1) and subtracting 25% (value in A2) to get 7.5. Obviously the formula for this could be something like: =(A2)+(A2)*B2/100. However, how do I create a formula for Cell A3 to reverse calculate this equation to get back to 10?. (8 + 25% = 10)

To try to explain, let me give you a different example. In the scenario below, the value of cell A3 should be 8. I get this value by taking the value of what Cell A3 should be (8) and adding the percent of Cell A2 (25%) which would give me the value of Cell A1 (10). I would like a formula that can calculate what should be in A3 based on the values in A1 and A2. ``Please Login or Register  to view this content.``  Register To Reply

2. ## Re: Formula to calculate value based on reverse percentage

Hi aharvestofhealth,

I get this value by multiplying what should be in Cell A3 (8) by Cell A2 (25%) which would give me the value of Cell A1 (10)
I get 8x25% = 2
how are you getting 10 ?

Regards,
DILIPandey

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3. ## Re: Formula to calculate value based on reverse percentage Originally Posted by dilipandey I get 8x25% = 2
how are you getting 10 ?
Sorry, poor wording. I meant 8 + 25% = 10. I've changed the wording in my original post.  Register To Reply

4. ## Re: Formula to calculate value based on reverse percentage

=a2*(1+a2)  Register To Reply

5. ## Re: Formula to calculate value based on reverse percentage

If:

B2 is 25
C2 is 7.5

then in A2 use: ``Please Login or Register  to view this content.``  Register To Reply

6. ## Re: Formula to calculate value based on reverse percentage

Ok... I guess its something like mathematical equations where we need to find the value of X - like we studied in our schools.. See :-
7.5=10-(10*(25/100))

Where 7.5 is A3 and 10 is A1

If you have A3 i.e, 7.5 and you would want to reach to A1 i.e, 10, you can use below equation:-

7.5=a-(a*(25/100))
7.5+(a*(25/100))=a
7.5+(a*0.25)=a
7.5=a-0.25a
7.5=0.75a
7.5/0.75=a
10=a This is equation solving in mathematics..

In excel you can use equation like :- 7.5/(1-25%) which would result in A

where you already had 7.5 and 25% with you. Regards,
DILIPandey

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7. ## Re: Formula to calculate value based on reverse percentage

I'm sorry guys. I've done a terrible job of explaining here. 7.5 is not the value I am looking for, it's 8. Let me start over to try this in a more simple fashion. Disregard everything I illustrated in my first post. Cell B2 and C2 are known values. As you can see from image1.JPG, Cell A2 is the value I'm trying to calculate - this number should be 8. Cell A2 (8) plus the percentage of B2 (25%) equals C2 (10). We can easily create a formula for C2 by using =A2+A2*B2/100. What I'm trying to find is the reverse and can be seen below:

X +25% = 10

Or in other words X + B2(%) = C2

X should be the formula for A2.  Register To Reply

8. ## Re: Formula to calculate value based on reverse percentage

=10/(1+25%)  Register To Reply

9. ## Re: Formula to calculate value based on reverse percentage Originally Posted by shg =10/(1+25%)

Thanks! The formula that I was actually looking for is this: ``Please Login or Register  to view this content.``
But you definitely pointed me in the right direction. The last part that I need for this is to be able to have it round to the nearest .05 or .09. In the past I've always used this formula to do that: ``Please Login or Register  to view this content.``
If there is a way to integrate that into C2/(1+B2%) , then that would be great. Also if it's possible to use ROUND instead, that would be preferred.

Sorry all, for making this so much more confusing then what it was.  Register To Reply