IF THEN CALCULATION

Hi, 

Want to enter a simple condition in calculation field in Podio: 

IF(@Conversion="Yes";@Principal*@InterestRate*@YearFracConverted; @Principal*@InterestRate*@YearFracNOTConverted) 

I've done the following in Podio: 

var Converted = @Converted
var prin = @Principal
var int = @Interest Rate
var fracc = @YearFracConversion
var frac = @YearFracNotConverted

Converted ="Yes" ? (prin*int*fracc) : Converted="No" ? (prin*int*frac) : ""

But is always gives me the result of "Yes" and never of "No"

Thanks for the help! 

Ben