Changing data value in Excel cell also overwrites function

[bobsampson]

I created a simple pounds and kilograms unit conversion. However when I try to change the value in the cell, it also overwrites the function. Is there any way to change the value without changing the function?  In the image below, I want to change the value of kilograms from 1587.6 to 1400 to see what it is in pounds. However when I double click the cell and change the value to 1400, it changes the function along with it to 1400. I would like to make it where the function is permanent and cannot be changed when I try to input a value of data. Thanks in advance! 

[#2]

@bobsampson 

That is not possible. A cell can contain a fixed value or a formula, not both.

But you can use VBA code to accomplish it.

See the attached workbook. You'll have to allow macros when you open it.

To view the code, right-click the sheet tab and select 'View Code' from the context menu.