Capital gains for a property rented just over 3 years

[Eric Peterson]

Can anyone tell me what happens if a home has been renting out for just over 3 years in terms of the capital gains exclusion. Do you lose the entire benefit or is there a sliding scale. 

Let's say you're trying to decide on selling a home after 2 years and 10 months of being rented vs waiting until 3 years and 4 months. Tenants living in the home want to extend the lease an extra 6 months because of building a home but the tax hit would be large if the capital gains tax has to be paid on the entire gain from when the home was purchased. 

I can't find anything that references this online and my CPA is out on vacation until next week.