How can I avoid showing a large percentage value?

I have a case where I have percentages that are extremely long, for example:

104.5%
26354736258475.4%

In the latter case, because my column width is a certain size, it will show a bunch of "#######". What I'd like to do is in such a case, show, "n/a" instead and I'd like to avoid using a macro.

Is there any simple formulas that can do this?

Thanks.

I think its caused your calculation. cause in percentage value maximum just 1. if your calculation is over then 1, for ex: 1.2 the result be 120%.