What is the normal time difference between London and Chicago?

London is usually 6 hours ahead of Chicago. London observes GMT (UTC+0) in winter and BST (UTC+1) in summer; Chicago observes CST (UTC-6) in winter and CDT (UTC-5) in summer. Both cities shift clocks in spring and autumn, keeping the gap at 6 hours for most of the year.

When is the time difference only 5 hours?

There are brief windows each year in March and late October/early November when the US and UK change clocks on different dates. During those transition periods, the gap shrinks to 5 hours instead of the usual 6 hours.

When does the UK change its clocks?

The UK moves clocks forward on the last Sunday in March at 01:00 GMT (becoming BST, UTC+1) and back on the last Sunday in October at 02:00 BST (returning to GMT, UTC+0).

When does Chicago (US Central) change its clocks?

The US shifts clocks forward on the second Sunday in March at 02:00 CST (becoming CDT, UTC-5) and back on the first Sunday in November at 02:00 CDT (returning to CST, UTC-6).

What are good meeting times for both London and Chicago?

The best overlap is 14:00–17:00 London time (08:00–11:00 Chicago time during the standard 6-hour offset). The meeting overlap finder on this page highlights those windows automatically.

Is this tool accurate for scheduling?

Yes. It uses the IANA timezone database embedded in your browser — the same source used by operating systems and calendar apps worldwide. Accuracy depends on your device clock being synchronized via NTP, which most devices do automatically.

Time Difference: London to Chicago

See the current time in London and Chicago side by side, with the exact hour offset and a business-hours overlap finder, updated live every second.

London, United Kingdom

--:--:--

GMT UTC+0

Chicago, United States

--:--:--

CST UTC-6

Current Offset

+6 hours

London is 6 hours ahead of Chicago

Meeting Overlap Finder

Business hours (09:00–18:00) highlighted — best overlap shaded

London	Chicago	Status

Convert London Time to Chicago Time

Based on the current offset — updates automatically

London	Chicago

Summary

This tool displays the live current time in both London (Europe/London — GMT in winter, BST in summer) and Chicago (America/Chicago — CST in winter, CDT in summer) side by side. The exact offset is calculated automatically and adjusts whenever either city transitions for Daylight Saving Time. Use it to schedule calls between the UK and US Midwest, coordinate remote teams, or check whether a colleague in Chicago is still at work.

How it works

Your browser reads the current moment from your device clock.
It converts that moment to Europe/London time using the IANA timezone database built into modern browsers.
The same moment is converted to America/Chicago time.
The UTC offsets of both cities are compared to calculate the exact hour difference.
All three values — London time, Chicago time, and the offset — refresh every second.
DST transitions for both cities are handled automatically, so the offset switches correctly each spring and autumn.

Use cases

Scheduling video calls between London and Chicago offices.
Checking if a colleague in Chicago is still at their desk.
Planning transatlantic travel and arrival time comparisons.
Remote teams coordinating daily standups across the UK and US Midwest.
Finding overlapping business hours for London-Chicago meetings.
Verifying whether both cities currently observe daylight saving time.
Journalists checking broadcast times for live Chicago events.
Students and teachers arranging online lessons across the Atlantic.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu