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BlogHow it works

GMT to CST Converter

Enter a GMT time and a date to see the time in the US Central zone. The converter switches from CST to CDT and back on the US daylight-saving dates.

Greenwich Mean Time

GMTGreenwich Mean Time

CSTCentral Time

––:––

CST
Also called Central Standard Time · US Central Time
Here CST means the US Central zone: UTC−6 in winter and UTC−5 (CDT) in summer, used in Chicago, Dallas, Houston, Minneapolis and New Orleans. Do not confuse it with China Standard Time, which shares the letters.

GMT to Central hour table

GMT timeGMT · CSTGMT · CDT
12:00 AM6:00 PM−1 previous day7:00 PM−1 previous day
1:00 AM7:00 PM−1 previous day8:00 PM−1 previous day
2:00 AM8:00 PM−1 previous day9:00 PM−1 previous day
3:00 AM9:00 PM−1 previous day10:00 PM−1 previous day
4:00 AM10:00 PM−1 previous day11:00 PM−1 previous day
5:00 AM11:00 PM−1 previous day12:00 AM
6:00 AM12:00 AM1:00 AM
7:00 AM1:00 AM2:00 AM
8:00 AM2:00 AM3:00 AM
9:00 AM3:00 AM4:00 AM
10:00 AM4:00 AM5:00 AM
11:00 AM5:00 AM6:00 AM
12:00 PM6:00 AM7:00 AM
1:00 PM7:00 AM8:00 AM
2:00 PM8:00 AM9:00 AM
3:00 PM9:00 AM10:00 AM
4:00 PM10:00 AM11:00 AM
5:00 PM11:00 AM12:00 PM
6:00 PM12:00 PM1:00 PM
7:00 PM1:00 PM2:00 PM
8:00 PM2:00 PM3:00 PM
9:00 PM3:00 PM4:00 PM
10:00 PM4:00 PM5:00 PM
11:00 PM5:00 PM6:00 PM
Each GMT hour with the Central time under CST and CDT. −1 marks the previous day in the US.

Working out a Central time from GMT

Subtract six hours in the US winter and five in the US summer. The switch happens at 2:00 AM local time on the second Sunday in March and the first Sunday in November, the federal dates explained by the US Department of Transportation. GMT itself is a fixed reference, Etc/GMT in the IANA time zone database, so it never moves.

Because of the size of the gap, anything before 06:00 GMT in winter, or 05:00 GMT in summer, is still the previous day in Chicago.

  1. Jan 1, 2026 – Mar 8, 2026GMT UTC+0 · CST UTC−6Difference: −6 h
  2. Mar 8, 2026 – Nov 1, 2026GMT UTC+0 · CDT UTC−5Difference: −5 h
  3. Nov 1, 2026 – Mar 14, 2027GMT UTC+0 · CST UTC−6Difference: −6 h
  4. Mar 14, 2027 – Nov 7, 2027GMT UTC+0 · CDT UTC−5Difference: −5 h
  5. Nov 7, 2027 – Dec 31, 2027GMT UTC+0 · CST UTC−6Difference: −6 h

Offsets in 2026 – 2027, from the IANA time zone data in your browser's engine

Energy, futures and the London link

Houston and Chicago are centers for oil, gas and futures trading, and many of their counterparts work on London hours. The overlap is the London afternoon and the Central morning: 14:00 GMT is 8:00 AM CST in winter, the start of the US trading day.

For calls with the UK in summer, remember that London is on BST and one hour ahead of the GMT shown here. A 3:00 PM meeting in London in July is 14:00 GMT, which is 9:00 AM in Dallas.

Before you send a GMT time to Texas

  • Say GMT or UTC, not just London time
  • Add the US date for early GMT hours
  • Use CDT from March to November
  • Write CT if unsure of the season
  • Recheck in March and November
  • Name the city for split states

See the live Houston clock, or convert the other way with CST to GMT.

GMT to CST questions

How many hours behind GMT is Central Time?

Six hours during CST (early November to mid-March) and five hours during CDT (mid-March to early November).

What is 15:00 GMT in Chicago?

9:00 AM CST in winter, or 10:00 AM CDT in summer.

Is this the CST used in China?

No. This page converts to US Central Standard Time (UTC−6). China Standard Time is UTC+8, eight hours ahead of GMT.

How far is London from Houston?

Six hours for most of the year, five for a few weeks in March and around the end of October when only one side has changed its clocks. This page uses fixed GMT; for UK local time see the London clock.