I am using USD as my main unit of convertion and another local PHP to my local fiat. if this calculator is real time in changing tbe price of per bitcoin it will be amazing... as now the coinsPH I am using to trade bitcoin to local money it is not real time and it gakes couple of minutes until it refresh.. annoying and also high fees..
btw good job that you created this simple algorythm and calculator but it is very common because there are many programs like these ever created before haha.. but again good job for you. make more 
I cant vissit the site because I am poor on internet haha Ph internet connection sucks.