Question : When converting a SQL database to unicode what is the size increase one should expect?

What is the increase in size I should expect in the database when the database is converted to Unicode?

Answer : When converting a SQL database to unicode what is the size increase one should expect?

all data stored in VARCHAR, changed to NVARCHAR, required 2 times the space used.
as varchar data is usually using most of the space, you should expect the database to grow up to 2 times the current size.