How long was Jesus's ministry? I've always heard, over in over, in Church and elsewhere that Jesus's ministry on Earth was only three years. However, it doesn't seem that there is much supporting Biblical evidence for this, or at least direct evidence. Nowhere does it say an exact period of time the events in the gospel where taking place over.

Is there evidence in the New Testament that we can reconstruct how long Jesus ministered for? If not then where does the three year figure come from?
Scholars who have attempted a synchronized harmony of the Gospels seem to indicate the Jesus went up to Jerusalem on three different occasions. From this, the tradition has grown up that his ministry was three years. 

Beyond this interpolation, however, there is nothing to suggest how long his earthly ministry actually lasted. As such, it is probably best to say his ministry lasted at least three years. 

Then again, after reading Mark keep saying "and he went immediately", you have gotten the impression it was just a few days :). But, overall, it does seem that the various times Jesus shows up in Jerusalem lend weight to at least 3 years.