Change From Foot To Meters

I have an Excel workbook that contains multiple shetts with multiple cells and complicated calulations.

i want to add 2 options:
1. Metric & Imperial Systems; where the user can select either system and based on that certain cell values will convert from one system to another. I decided to standardize the workbook with Imperial (square foot) and then the user can if desired change into metric (square meters). I have designed all the necessary cells (selection & factor from foot to meter). My challenge now is to convert all the cells that is in Sq. Foot to Sq. Meters and vice versa. I comcluded that it cannot be done without a macro. Does anyone have an idea how to achieve that without duplicating all cells?

2. I have the same problem ad 1 above with currencies. I believe once i solve 1 i can solve this one.

So my first question is "Is there any easy way of figuring out which cells are in Sq. Foot or Sq Meters and converting them accordingly? if not I would have to write a macro and specify each cell reference there. Never mind the fact that with my modest VBA knowledge i can't write such a macro.