Three hours, coast to coast
Eastern to Pacific is a subtraction of three hours, and because both zones follow the same daylight-saving calendar the gap holds steady through the year. Noon in New York is 9:00 AM in Los Angeles in every month.
The overlap problem
Three hours is the widest gap in the mainland United States and it eats most of the shared working day. If both coasts keep 9-to-5 local hours, the genuine overlap runs from noon to 5:00 PM Eastern, which is 9:00 AM to 2:00 PM Pacific. That is five hours, and it disappears fast once you subtract lunch. A 9:00 AM Eastern kickoff is 6:00 AM in San Francisco; a 4:00 PM Pacific demo is 7:00 PM in New York. Teams that span both coasts usually settle on a late-morning Eastern slot and defend it.
Deadlines quoted in Eastern
Filing windows, ticket sales, market hours and product launches are routinely announced in Eastern. From the West Coast that shifts everything earlier: the New York market opens at 6:30 AM Pacific, and a “11:59 PM Eastern” cut-off expires at 8:59 PM Pacific, still the same evening. Treat any Eastern deadline as roughly a working afternoon shorter than it appears.
What the abbreviations really mean
For most of the year the correct pair is EDT and PDT, not EST and PST. The three-hour difference is identical either way, so the loose usage rarely causes harm on this route. It matters only when someone means strict, never-shifting PST at UTC−8 while the West Coast is actually on PDT at UTC−7.