how do you calculate a mortgage?

[Shawn Mcenteer]

I am looking to purchase a property for $190k w/ 5% down fixed rate. Taxes are $6,800 per yer. It comes out to be about 1700 per month = $20400 per year. Take the taxes out it comes out to be $13,600 per yr. The mortgage is 30yrs but when i do the math it comes out to be $408K im paying over 30 years. Is this correct? Should a mortgage really be more than double the cost of the home over 30years?