US Business Hours by Time Zone: A Quick Reference

Most US offices operate roughly 9 AM to 5 PM in their own local zone. In UTC terms, that's 14:00–22:00 UTC for Eastern (standard time), 15:00–23:00 UTC for Central, 16:00–00:00 UTC for Mountain, and 17:00–01:00 UTC for Pacific.

Because Eastern and Pacific are three hours apart, there's only a four-hour window each day — roughly 12 PM–4 PM Eastern (9 AM–1 PM Pacific) — when all four contiguous US zones are simultaneously within standard 9-to-5 hours.

Scheduling a call, meeting, or livestream inside that window is the most reliable way to reach the whole contiguous US during business hours without asking anyone to start unusually early or stay unusually late.

Alaska is one hour behind Pacific and Hawaii is three hours behind Pacific (without observing daylight saving), so a truly nationwide, all-fifty-states overlap window shrinks further — typically landing around 1 PM–2 PM Eastern for a comfortable overlap with Hawaii's morning too.

The UTC times listed above shift by an hour twice a year as each zone moves between standard and daylight time, but the relative spacing between zones — one hour apart from each neighbor — never changes, since Eastern, Central, Mountain, and Pacific all shift on the same two dates.

Companies that schedule nationwide store hours, customer support coverage, or broadcast windows typically build their systems around local time rather than UTC directly, precisely to avoid needing to manually re-calculate offsets every March and November.

Businesses with a genuinely nationwide footprint, including Alaska and Hawaii, often publish separate stated hours for those two markets rather than trying to force them into the same overlap window used for the contiguous 48 states.