Selling a mortgaged home

[Nur Al Sharif]

Hi all,

I've been running some numbers trying to understand long-term gains on residential real estate investments, and came across a scenario that I can't wrap my head around. 

If I take out a $331,500 mortgage at 4% over 30 years (on a $440,000 property), my monthly mortgage payment will be $1582.63. Multiply this by periods 360 = a total payment over 30 years of $569,747.41. 

Say in 5 years time I decide to sell the property, at $440,000, having paid down a small part of the mortgage principal. The total payment remaining on the mortgage would be $474,489.51. Would selling the house result in a net loss due to covering the interest on the mortgage? Or is my understanding of mortgages completely wrong? 

The main thing here is wondering which mortgage balance would be subtracted from the sale of the home (is it the principal remaining, or the total payment that was scheduled to take place over 30 years?)

Thanks in advance, 

Newbie