Fixed vs. Variable
With fixed rate mortgage (FRM) loan the interest rate and your mortgage monthly payments remain fixed for the period of the loan. Fixed-rate mortgages are available for 30, 25, 20, 15 years and 10 years. Generally, the shorter the term of a loan, the lower the interest rate you could get.
The most popular mortgage terms are 30 and 15 years. With the traditional 30-year fixed rate mortgage your monthly payments are lower than they would be on a shorter term loan. But if you can afford higher monthly payments a 15-year fixed-rate mortgage allows you to repay your loan twice as fast and save more than half the total interest costs of a 30-year loan.
A vVariable or adjustable loan is a loan whose interest rate, and accordingly monthly payments, fluctuate over the period of the loan. With this type of mortgage, periodic adjustments based on changes in a defined index are made to the interest rate. The index for your particular loan is established at the time of application.
The margin is fixed percentage points added to the index to compute the interest rate. The result will then be rounded to the nearest one-eighth of a percent.
Example:
The index is 5.3% and the margin is 2.5%,
then the new interest rate = 5.3% + 2.5% = 7.8%.
The nearest to 0.8% is 0.75% = 6/8%.
The result will be 7.75%.
The margins remain fixed for the term of the loan and are not impacted by the financial markets and movement of interest rates. Lenders use a variety of margins depending upon the loan program and adjustment periods.
Most ARMs have an interest rate caps to protect you from enormous increases in monthly payments. A lifetime cap limits the interest raincrease over the life of the loan. A periodic or adjustment cap limits how much your interest rate can rise at one time.
Examples:
1. The initial interest rate is 4.5%, the index is 7%, and the margin is 3%,
then the new interest rate = 7% + 3% = 10%.
If the lifetime cap is 5% then
the actual new interest rate will be 4.5% + 5% = 9.5%.
2. The initial interest rate is 6%, the index is 5%, and the margin is 3%,then the new interest rate = 5% + 3% = 8%.
If the periodic cap is 1% then the actual new interest rate will be 6% + 1% = 7%.
Your mortgage disclosure will tell you the exact index, to be used, whether the weekly or monthly value applies, the lead time for your index, the margin, and any caps.

