CET vs EST — cities and working rhythm
Most of continental Europe — DACH, Benelux, France, Iberia, Nordics (except Finland), Poland, Czech Republic. Business hours 9 AM – 5:30 PM CET, with a longer lunch (12:30 – 2 PM) in southern countries. Winter: CET (UTC+1); summer: CEST (UTC+2). Big lag against North America — early morning CET overlaps late night ET.
US East Coast — the reference clock for US business, Wall Street, US law and consulting firms, most Fortune 500 HQ. Business hours 9 AM – 6 PM ET. Note: EST is the winter offset (UTC-5); EDT (UTC-4) is the summer offset — "ET" is the year-round non-committal way to refer to this zone in scheduling apps.
Time gap: EST is 6.0 hours behind CET (standard-time offsets — daylight-saving flips shift this by an hour twice a year in most northern-hemisphere zones).