Percentage increase at a decreasing rate

[VCHarry]

Hi guys,

I am building a financial model on a monthly basis. As part of the revenue build I want to grow a percentage at a decreasing rate. For example, over a 12 month period I want the percentage to increase from 50% to 95% with the greatest increase happening at the start and then increasing at a decreasing rate. I also want this to be dynamic in that the user can change the starting percent, ending percent and time span. I have been trying to work with depreciation formulas and exponential formulas but I'm having no luck! Can anyone help?

Much appreciated!

Harry.

 

[Eric W]

Welcome to the forum.

It depends on what kind of slope you want. For example, a logarithmic curve has that property, of constantly getting larger, but at slower and slower rates. If you scaled the curve to your requirements, you'd get what you want. For example:

	A	B	C

<colgroup><col style="width: 25pxpx"><col><col><col></colgroup><thead>
</thead><tbody>
[TD="align: center"]1[/TD]
[TD="align: right"]50[/TD]
[TD="align: right"]95[/TD]
[TD="align: right"]50.00[/TD]

[TD="align: center"]2[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]61.68[/TD]

[TD="align: center"]3[/TD]
[TD="align: right"]12[/TD]
[TD="align: right"][/TD]
[TD="align: right"]68.95[/TD]

[TD="align: center"]4[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]74.23[/TD]

[TD="align: center"]5[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]78.38[/TD]

[TD="align: center"]6[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]81.81[/TD]

[TD="align: center"]7[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]84.72[/TD]

[TD="align: center"]8[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]87.25[/TD]

[TD="align: center"]9[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]89.50[/TD]

[TD="align: center"]10[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]91.51[/TD]

[TD="align: center"]11[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]93.33[/TD]

[TD="align: center"]12[/TD]
[TD="align: right"][/TD]
[TD="align: right"][/TD]
[TD="align: right"]95.00[/TD]

</tbody>

Sheet1​

[TABLE="width: 85%"]
<tbody>[TR]
[TD]Worksheet Formulas[TABLE="width: 100%"]
<thead>[TR="bgcolor: #DAE7F5"]
[TH="width: 10px"]Cell[/TH]
[TH="align: left"]Formula[/TH]
[/TR]
</thead><tbody>[TR]
[TH="width: 10px, bgcolor: #DAE7F5"]C1[/TH]
[TD="align: left"]=$A$1+($B$1-$A$1)*LOG(1+9*(ROW()-1)/($A$3-1))[/TD]
[/TR]
</tbody>[/TABLE]
[/TD]
[/TR]
</tbody>[/TABLE]



A1 has the starting percent, B1 has the ending percent, and A3 has the number of steps. Let me know if this works for you.