Time difference in US - East and West coast time zones

What is the time difference between East coast and West coast in US ? For example between New York and Los Angeles ? How many time zones are in US in total ?

There are 4 standard time zones for the continental United States:

• Eastern time zone
• Central time zone (+1 hour)
• Mountain time zone (+1 hour)
• Pacific time zone (+1 hour)

The time difference between New York on east coast and Los Angeles on west coast is 3 hours.

But in total there 9 standard time zones in the US: Atlantic, Eastern, Central, Mountain, Pacific, Alaska, Hawaii, Samoa and Chamorro.