Usually 2-3 weeks. Pink eye or viral conjunctivitis is usually an acute condition caused by adenovirus (like the common cold). Most cases will resolve in a few weeks but some can be prolonged. There are many other causes of conjunctivitis so any additional or more severe symptoms should be examined by your eye doctor.
Days or weeks! If pink eye is caused by bacteria, it will resolve in less than 7 days, usually 5. Antibiotic drops shorten the duration to around 3 days. Unfortunately, viral conjuctivitis is caused by the same types of viruses that cause the common cold. And just like a cold, they have to run their course. Patients are usually affected for 10 days to 2 weeks, and are very contagious for about 10 days.