Refinancing is when you take out a new mortgage on your home, at a lower interest rate, decreasing the amount of your monthly mortgage payment. In some creative refinancings, you can also increase the amount of the loan for such in order to paying down your credit card debt or making some stock investment.

Mortgage interest is tax-deductible, so to calculate the effective yield of a mortgage, multiply the interest rate by your tax bracket. Then subtract that from your interest rate.