There is not any doubt that Calvin taught that we are justified by the imputed righteousness of Christ (see Institutes of the Christian Religion, Book 3, Chapter 13, and Book 4, Chapter 14). Moreover, in general it seems that most Reformed historians conclude with Francis Turretin that Calvin taught that specifically the active obedience of Christ, and not only his passive obedience, is imputed to believers.
Nevertheless, since the question of whether Calvin taught that the active obedience of Christ is imputed to believers, I thought I would provide a link to Cornelius Venema’s careful treatment of the matter (link to pdf), in contrast to certain rash treatments of the matter that exist.
The very short answer is that the “active/passive” distinction is a later development, but Calvin’s doctrine with respect to imputation is more consistent with the imputation of active obedience, because he distinguishes between imputation of righteousness and forgiveness of sins, and because he treats all of Christ’s obedience as indispensable.
– TurretinFan
Thoughts of Francis Turretin 