The Master of Architecture (M.Arch.) degree is the title denoting a collection of two different levels of a Master's degree in Architecture. Many schools offer both tracks and they range from 1 to 5 years, usually called M.Arch I and M.Arch II).
M.Arch I is a first professional degree available to students who have already earned a 4 year undergraduate degree. Program length for those with a pre-professional degree in architecture (BA, BS, etc. in architecture) is, typically, 2 years in length, while those with an undergraduate degree in another discipline study for 3 years.
M.Arch II is a post-professional degree involving between a year and two years (depending on which school) of intensive focused work for students that already have a 5-year Bachelor's of Architecture degree.