Time difference between Chicago and Sydney
Chicago CDT · UTC-5 
Sydney GMT+10 · UTC+10 Best time to call
Hours shown in Chicago time. The two working days never overlap: when Chicago is at its desk, Sydney is asleep. Schedule at the edge of one side's day.
Hour-by-hour conversion
| Chicago (CDT) | Sydney (GMT+10) | Call quality |
|---|---|---|
| 12:00 AM | 3:00 PM | Off hours |
| 1:00 AM | 4:00 PM | Off hours |
| 2:00 AM | 5:00 PM | Off hours |
| 3:00 AM | 6:00 PM | Off hours |
| 4:00 AM | 7:00 PM | Off hours |
| 5:00 AM | 8:00 PM | Off hours |
| 6:00 AM | 9:00 PM | Off hours |
| 7:00 AM | 10:00 PM | Off hours |
| 8:00 AM | 11:00 PM | Off hours |
| 9:00 AM | 12:00 AM+1 day | Off hours |
| 10:00 AM | 1:00 AM+1 day | Off hours |
| 11:00 AM | 2:00 AM+1 day | Off hours |
| 12:00 PM | 3:00 AM+1 day | Off hours |
| 1:00 PM | 4:00 AM+1 day | Off hours |
| 2:00 PM | 5:00 AM+1 day | Off hours |
| 3:00 PM | 6:00 AM+1 day | Off hours |
| 4:00 PM | 7:00 AM+1 day | OK |
| 5:00 PM | 8:00 AM+1 day | OK |
| 6:00 PM | 9:00 AM+1 day | OK |
| 7:00 PM | 10:00 AM+1 day | OK |
| 8:00 PM | 11:00 AM+1 day | OK |
| 9:00 PM | 12:00 PM+1 day | OK |
| 10:00 PM | 1:00 PM+1 day | Off hours |
| 11:00 PM | 2:00 PM+1 day | Off hours |
Daylight saving time note
Chicago and Sydney do not change their clocks on the same date. Between October 3, 2026 and November 1, 2026 the difference is 16 hours behind Sydney — because Chicago and Sydney switch daylight saving time on different dates.
For the rest of the year the difference holds steady at 15 hours. Every time on this page is computed from the IANA database at the moment you load it, so the tables above already account for whichever side has switched.
Why the time difference exists
Chicago uses UTC-6 as its standard offset and Sydney uses UTC+10. Each springs forward in its own summer — and those summers are six months apart — so the difference swings back and forth across the year. Sydney sits roughly 14,900 km to the west of Chicago.
Expect roughly a 8 hours backward adjustment travelling from Chicago to Sydney. The direct distance works out to roughly 18 hours in the air. Line up a shared window before you call and the rest is easy.
