Most people are able to hold their breath for about two minutes. The world record for length of time that a man was able to hold his breath is about 20 minutes. This record was set by Ricardo Bahia. Right before holding his breath for this long Bahia also had the benefit of breathing pure oxygen as well.
No matter the time you are able to hold your breath you will always start breathing again. A person cannot die from holding their breath because eventually they will pass out and begin breathing again automatically. Breathing is a function that the body automatically performs.