There are many types of mortgage loans. The two basic types of amortized loans are the fixed rate mortgage (FRM) and adjustable rate mortgage (ARM).

In a FRM, the interest rate, and hence monthly payment, remains fixed for the life (or term) of the loan. In the U.S., the term is usually for 10, 15, 20, or 30 years. The only increase a consumer might see in their monthly payments would result from an increase in their property taxes or insurance rates (paid using an escrow account, if they've opted to use an escrow). But payments for principal and interest will be consistent throughout the life of the loan using an FRM.

In an ARM, the interest rate is fixed for a period of time, after which it will periodically (annually or monthly) adjust up or down to some market index. Common indices in the U.S. include the Prime Rate, the London Interbank Offered Rate (LIBOR), and the Treasury Index ("T-Bill"). Other indexes like 11th District Cost of Funds Index, COSI, and MTA, are also available but are less popular.

Adjustable rates transfer part of the interest rate risk from the lender to the borrower, and thus are widely used where unpredictable interest rates make fixed rate loans difficult to obtain. Since the risk is transferred, lenders will usually make the initial interest rate of the ARM's note anywhere from 0.5% to 2% lower than the average 30-year fixed rate.

In most scenarios, the savings from an ARM outweigh its risks, making them an attractive option for people who are planning to keep a mortgage for ten years or less.

Additionally, lenders rely on credit reports and credit scores derived from them. The higher the score, the more creditworthy the borrower is assumed to be. Favorable interest rates are offered to buyers with high scores. Lower scores indicate higher risk to the lender, and lenders require higher interest rates in such scenarios to compensate for increased risk. Mortgage Info at Blogspot.com

A partial amortization or balloon loan is one where the amount of monthly payments due are calculated (amortized) over a certain term, but the outstanding principal balance is due at some point short of that term. This payment is sometimes referred to as a "balloon payment". Mortgage Info at Blogspot.comA balloon loan can be either a Fixed or Adjustable in terms of the Interest Rate. Many Second Trust mortgages use this feature. The most common way of describing a balloon loan uses the terminology X due in Y, where X is the number of years over which the loan is amortized, and Y is the year in which the principal balance is due. A contract could be written up so there would be more than one "balloon payment" required to be paid during the life of the loan.