A Conventional loan refers to a loan that is not insured or guaranteed by the federal government. A conventional, or conforming mortgage adheres to the guidelines set by Fannie Mae or Freddie Mac. This loan can have an interest rate that is either fixed or adjustable (ARM).
Fixed Mortgages is when the interest rate is locked in for the life of the loan that is typically 15 or 30 years. An ARM has a lower introductory rate for a fixed period of time followed by periodic adjustments. Payments for Arms are amortized over a 30 year term.