Atlanta is 1 hour ahead of Chicago. Chicago uses Central Time (CT, UTC-6/-5) while Atlanta uses Eastern Time (ET, UTC-5/-4). When it's 12:00 PM in Chicago, it's 1:00 PM in Atlanta.
Both cities observe daylight saving time on the same schedule, so the 1-hour difference remains constant year-round.
Best calling time: 8:00 AM - 5:00 PM Chicago time. This corresponds to 9:00 AM - 6:00 PM in Atlanta, covering standard business hours.
Chicago and Atlanta are two of America's major business hubs. Both are major airline hub cities - Chicago O'Hare is a United hub while Atlanta Hartsfield-Jackson is the world's busiest airport and Delta's main hub. Direct flights take about 2 hours.