What are the minimum number of stages in PRINCE2?

In PRINCE2 there is a minimum of two management stages in a project. Every project always has an initiation stage plus one further management stage.

How many stages your project should have depends upon several factors including the 'planning horizon', which refers to how far into the future it is sensible to plan in detail. It is unwise to try to plan beyond this and therefore it is best to set a management stage boundary at the planning horizon.

Also, the level of risk will affect the number of stages. The greater the risk, the shorter the management stages will be (hence there will be more stages). The lower the risk the fewer stages are required.