Hi, I am a 12+ years programmer with more than 6 years' experience in javascript and jquery. I can create your calculator in javascript, and you will be able to upload it to every site you want (php, c#, anything).
I do not know the complexity of the calculator but I think my bid is reasonable. If upon analysis I see it is too much (or too little) I will adjust previous to sealing the deal.
Looking forward to work with you.
Diego