There is no overlap between 09:00–18:00 working days in these two places.
How many hours is CST behind JST?
As abbreviations, JST is always 15 hours ahead of CST: CST is UTC−6 and JST is UTC+9. To convert, add 15 hours.
When the CST to JST time difference changes
For most of the year JST is 14 hours ahead of CST. From 1 November to 31 December 2026, JST is 15 hours ahead of CST instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
Dates
JST vs CST
Length
1 November 2026 to 31 December 2026
15 hours ahead
61 days
1 January 2027 to 13 March 2027
15 hours ahead
72 days
14 March 2027 to 6 November 2027
14 hours ahead
238 days
7 November 2027 to 31 December 2027
15 hours ahead
55 days
When CST and JST are both at work
When JST is 14 hours ahead of CST: no shared 09:00 to 17:00 hours; try 17:00 in CST (07:00 in JST).
When JST is 15 hours ahead of CST: no shared 09:00 to 17:00 hours; try 17:00 in CST (08:00 in JST).
Frequently asked questions about CST and JST time
How many hours ahead is JST of CST?
JST (UTC+9) is 15 hours ahead of CST (UTC−6).
Does the time difference between CST and JST change?
Yes. It is usually 14 hours ahead, but changes when one side moves its clocks: 15 hours ahead from 1 November to 31 December 2026; 15 hours ahead from 1 January to 13 March 2027.