Sales prediction/extrapolation formula

[bsinatra24]

Hi All,
Using v. 2016
Here's what I'm trying to do. I want to calculate the predicted sales trend for the remainder of this year (2017). here's my data:

Jan-80, Feb-80, Mar-92, Apr-120, May-?, Jun-?, etc.

Feb's increase was 0%, March's increase was 15%, April's increase was 30.43%. What will be May's increase, and the subsequent months be until year-end?

I'm assuming I take the average % increase from the prior months to determine the following and future months (which seems logical).

So, first question: Do I take 0+15+30.43 divided by 3 (15.14%) or 4 (11.36%)?

2nd question: Regardless of the answer to Q1, how do I then include May's predicted increase into a "prediction formula" for June (which will now be 4 numbers divided by either 4 or 5); and so forth for the remaining months?
The predicted number for June will be calculate into the previous months' average increase, and thus predict the increase for July, and so on.

Is there a formula to predict numbers from previous months' know data and months yet to occur based on that real & predicted data?

Hopefully this makes sense. I'll admit, I got confused as I was typing haha. Anyways, would be great to hear any ideas or suggestions. Let me know if you need any more clarification, and I'll try to explain a little better.

Sidebar - Do you recommend trying this in cells only, or would creating a graph help in anyway? I'd like to do the formulation & predicted trend first, and then create a graph afterwards; but if a graph helps with the formula, let me know.

Thanks!

-B

[sandy666]

Attach a sample workbook not a picture. Make sure there is just enough data to demonstrate your need. Include a BEFORE sheet and an AFTER sheet in the workbook if needed to show the process you're trying to complete or automate. Make sure your desired results are shown, mock them up manually if necessary.

Remember to desensitize the data.

Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.