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DST Checker: Daylight Saving Time Status and Clock Change Dates

This free tool tells you whether daylight saving time (DST) is in effect on a date in any time zone. It shows the UTC offset, the standard offset and the dates and times when the clocks change in that year.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

DST changes catch people out every year. Meetings, flights, servers and schedules can move by an hour.

Pick a date and a zone to see the status and the change dates.

How to Use This Tool

  1. Enter or paste your input in the box or boxes above.
  2. Choose the options, if there are any.
  3. Press the button to run the tool.
  4. Read the result and use the copy button where one is shown.

How the Calculation Works

The tool reads the UTC offset of the zone at noon on your date using the browser's international date functions. It then looks at every day of the year to find days when the offset changes, and narrows each change down to the minute. DST is on when the current offset is larger than the smallest offset of the year.

Worked Example

In New York on 1 July 2025 the offset is UTC-04:00 and DST is on. Clocks went forward on 9 March 2025 and go back on 2 November 2025.

Common Uses

  • Planning meetings and travel.
  • Server and cron schedules.
  • Checking old timestamps.
  • Teaching time zones.

Tips and Common Mistakes

  • Southern hemisphere zones have DST in their summer, our winter.
  • Use full zone names such as Europe/Madrid, not abbreviations like CET.
  • Check official sources for legal time rules.
  • Check the first result against a case you already know, so you can trust the tool for the rest.
  • Nothing you type leaves your device. The work is done by your browser, so it also works with a slow connection once the page has loaded.

Next, you may need the time zone converter, Unix timestamp converter, day of the week calculator, date difference calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

The practice of moving clocks forward in spring and back in autumn to make better use of daylight. Many places do not use it.
It compares the zone's offset on your date with its smaller offset in the same year. A bigger offset means DST.
From your browser, which uses the IANA time zone database. Rules for future years can change, so update your browser.
Zones such as Kolkata, Tokyo, Dubai and UTC do not use DST.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.