A mortgage is a secured loan in which an asset is given as a security against the loan to acquire that asset. This is most useful when you want to purchase a house. You can take a loan giving the house as security and acquire and reside in the same. There are no issues as long as you make prompt monthly payments.
The problem arises when you make any default on the loan. At this time, the lender can take possession of the house, sell the same and realize the loan. Thus, the risk of the lender is reduced and this should spell as lower interest rates for you. But this does not always happen; many borrowers do not do the groundwork before taking the loan. Thus, they are stuck with ones that have unfavorable interest rates.
At some other times, the market interest rates themselves may fall. This may also seem very unfair to you. You will be stuck with high interest rates while all others may have pretty favorable terms. The best way to resolve this problem is to refinance your loan. That is, you should take a new loan with a favourable rate to replace the previous one with a higher rate.
When you decide to refinance, the mortgage refinance calculator rate should be determined for the various options available and a wise choice should be made. It is better to make the comparisons in absolute terms as this will give you the clear and complete picture.