12pm in London is 6am in Chicago
MEETING PLANNER
hover a column · click to lockLondon is 6 hours ahead of Chicago. Chicago runs on America/Chicago (UTC-5); London runs on Europe/London (UTC+1). The difference is measured right now; it can shift by one hour during daylight-saving-time transitions.
Both Chicago and London observe daylight saving time, but their transition dates are not identical. Chicago shifts between CST (UTC-6) and CDT (UTC-5); London shifts between GMT (UTC+0) and BST (UTC+1). The difference between them stays close to 6 hours across most of the year, with short mismatch windows around each city’s transition when the gap briefly widens or narrows by an hour.
Standard 9-to-5 business hours in Chicago and London overlap for roughly 2 hours a day. That window lands at 09:00–11:00 in Chicago and 15:00–17:00 in London. Teams with real-time coordination needs anchor cross-city calls inside it: long enough to cover handovers, short enough that it forces crisp agendas. Outside that window, async is the default — shared docs, recorded updates, and scheduled follow-ups rather than live meetings.
When planning recurring meetings across Chicago and London, pin them to one city’s local time rather than UTC or the other city’s clock. That way, the meeting time stays stable for the person anchoring the schedule, and the other side absorbs the one-hour drift during DST transitions. The alternative — a meeting pinned to the non-DST city — means the DST city sees the meeting time “move” twice a year, which is how recurring calendar invites end up at 7am on someone’s calendar in October.
- What is the time difference between Chicago and London?
- London is currently 6 hours ahead of Chicago. Chicago is on America/Chicago (UTC-5); London is on Europe/London (UTC+1). The offset shifts by one hour during daylight-saving transitions — the difference is 6 hours in winter and 6 hours in summer.
- Do Chicago and London observe daylight saving time?
- Both cities observe daylight saving time. Chicago uses CST in winter and CDT in summer; London uses GMT in winter and BST in summer. Their transition dates can differ by a week or two, which briefly widens or narrows the offset during the changeover period.
- When do business hours overlap between Chicago and London?
- Standard 9-to-5 business hours overlap for about 2 hours per day — roughly 09:00–11:00 in Chicago and 15:00–17:00 in London. Cross-city calls typically land inside that window.
Frequently Asked Questions
What is the time difference between Chicago and London?
London is currently 6 hours ahead of Chicago. Chicago is on America/Chicago (UTC-5); London is on Europe/London (UTC+1). The offset shifts by one hour during daylight-saving transitions — the difference is 6 hours in winter and 6 hours in summer.
Do Chicago and London observe daylight saving time?
Both cities observe daylight saving time. Chicago uses CST in winter and CDT in summer; London uses GMT in winter and BST in summer. Their transition dates can differ by a week or two, which briefly widens or narrows the offset during the changeover period.
When do business hours overlap between Chicago and London?
Standard 9-to-5 business hours overlap for about 2 hours per day — roughly 09:00–11:00 in Chicago and 15:00–17:00 in London. Cross-city calls typically land inside that window.