Time Zone Converter

Convert dates and times between CT, GMT, UTC and world cities. Add or subtract hours and minutes with daylight saving time support.

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Local date and timeFrom time zoneTo time zoneAdd or subtract hoursAdd or subtract minutesClock-change conflicts

CT, ET, MT and PT follow the displayed US city and its daylight saving rules. Other abbreviations are fixed offsets. Use a city for automatic clock changes. Calculations add elapsed time; negative numbers subtract it.

Output

How it works

Choose a local date and time, source and destination time zones. Optionally add or subtract elapsed hours and minutes, then run the conversion. For daylight saving conflicts, check the time or explicitly select the earlier or later instant.

A practical example

Local date and time

2026-07-01T09:00

Result

CT → GMT: 14:00

Frequently asked questions

Why can the time difference change during the year?

City time zones can switch between standard time and daylight saving time, sometimes on different dates. The converter uses the selected date to apply those rules. Fixed offsets such as GMT stay unchanged; choose a city zone when you need its seasonal rules.

Is my input sent to a server?

No. Your content is processed in this browser. It is never sent to the server or saved.

What should I know about Time Zone Converter?

CT uses Chicago rules; CST means North American UTC−06:00, while GMT is fixed at UTC+00:00. City rules depend on browser time-zone data. Ambiguous or missing local times require an explicit choice.