How to convert units of input cells automatically

[haroocivil]

HI,

I HAVE DATA INPUTS IN CELLS A1 TO A5.
I WANT VALUES IN "INPUT CELL "TO CHANGE BASED ON UNIT SYSTEM (METRIC SYSTEM OR BRITISH SYSTEM) IF SELECTED AT FIRST.
it is important to consider that that values in CELL A1 TO A5 ARE "INPUTS"

FOR EXAMPLE

Select Units Metric System DATA INPUTS 8000 Cumecs 50 meter 300 meter 400 meter 90 meter <tbody> </tbody>

<tbody>
</tbody>