Capacity Management - User Profile Service limits

Limit	Maximum value	Limit type	Notes
User profiles	2,000,000 per service application	Supported	A user profile service application can support up to 2 million user profiles with full social features functionality. This number represents the number of profiles that can be imported into the people profile store from a directory service, and also the number of profiles a user profile service application can support without leading to performance decreases in social features.
Social tags, notes and ratings	500,000,000 per social database	Supported	Up to 500 million total social tags, notes and ratings are supported in a social database without significant decreases in performance. However, database maintenance operations such as backup and restore may show decreased performance at that point.