Most adjustable rate mortgages have an initial period of a fixed rate (usually 3 or 5 years), and then convert to fully adjustable each year. The floating rate is usually agreed to be some publicly available interest rate (for example, LIBOR, constant maturity treasuries or CMT) plus a spread. The spread is determined based on your credit worthiness. Lots of websites can give you historical rates for these. Bankrate.com can give you current average rates on mortgages and other loans (and deposits).
Most adjustable rate mortgages have an initial period of a fixed rate (usually 3 or 5 years), and then convert to fully adjustable each year. The floating rate is usually agreed to be some publicly available interest rate (for example, LIBOR, constant maturity treasuries or CMT) plus a spread. The spread is determined based on your credit worthiness. Lots of websites can give you historical rates for these. Bankrate.com can give you current average rates on mortgages and other loans (and deposits).