These days, 5/25 and 7/23 convertible balloon mortgages are gaining popularity since they provide lower rates than conventional 30 year mortgages while still maintaining a fixed payment schedule for 5 or more years. The risk, of course, is what can happen after the initial fixed period is over and rates change. You have the possibility of converting your loan; but what kind of interest payments would you be facing otherwise? Here is a calculator to help answer those questions...