Why does the offset change throughout the year?

Chicago observes Daylight Saving Time (clocks move +1 hour in spring and back in fall). Tokyo stays at UTC+9 all year. The offset is 14 hours when Chicago is on CDT (UTC-5) and 15 hours when Chicago is on CST (UTC-6).

What time zones does this tool use?

Tokyo uses the Asia/Tokyo IANA zone (JST, UTC+9 always). Chicago uses America/Chicago (CST UTC-6 in winter / CDT UTC-5 in summer).

Does this handle Daylight Saving Time automatically?

Yes. The tool uses the JavaScript Intl API with named IANA zones, so DST transitions are handled by your browser automatically.

What if the converted Chicago time rolls back past midnight?

The tool handles wrap-around and labels times that fall on the previous day with a "-1 day" badge so there is no ambiguity.

Is there a good overlap window for Tokyo and Chicago business hours?

Overlap is very limited. Tokyo business hours (9 AM–5 PM JST) correspond to roughly 6 PM–2 AM CST (or 7 PM–3 AM CDT) in Chicago, so early Tokyo morning meetings or late Chicago evening calls are typically needed.

Time Difference: Tokyo to Chicago

See live Tokyo and Chicago clocks side by side, the exact hour offset, and convert any Tokyo hour to Chicago time instantly.

Tokyo

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JST (UTC+9)

Current Offset

hours ahead

(Tokyo ahead of Chicago)

Chicago

--:--:--

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Tokyo Hour to Chicago

Select Tokyo hour

Business Hours Overlap

Tokyo business hours (9 AM – 5 PM) vs Chicago equivalent:

Summary

Tokyo (Asia/Tokyo, JST UTC+9) is 14 or 15 hours ahead of Chicago (America/Chicago) depending on US Daylight Saving Time. This tool shows both live clocks, calculates the current offset automatically, and lets you select any Tokyo hour to see the exact corresponding Chicago time.

How it works

Your browser reads the current UTC time.
It converts UTC to Tokyo local time (Asia/Tokyo, UTC+9, no DST).
It converts UTC to Chicago local time (America/Chicago, respecting CST/CDT).
The offset is computed as the difference between the two local times.
When you pick a Tokyo hour from the selector, the tool subtracts the offset to show the Chicago equivalent.

Use cases

Schedule a call between a Tokyo office and a Chicago partner.
Check whether Chicago colleagues are still in the office when you start your Tokyo morning.
Plan webinars or live streams that span both cities.
Quickly verify what time a Tokyo deadline falls in Chicago.
Calculate overlap windows for remote teams split across Japan and the US Midwest.

Frequently Asked Questions

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