How to use it
- Type the Time zone of the place, such as Europe/London or America/New_York.
- Choose the Year.
- Read Daylight saving starts and Daylight saving ends. The Clock time at the change is the reading on the clock when it changes.
- Open the table to see every change of offset in the year, including any that is not a daylight saving change.
How the dates are found
The dates come from the time zone data built into your browser, read through the Intl API. Zone names are IANA names: the IANA time zone database is the public collection that records the local time rules of each zone and their history. This page keeps no copy of it, so the dates follow the version of the data your browser has.
The offset is read every hour across the year, and each change is narrowed down to the minute. Daylight time is the larger of the January and July offsets and standard time the smaller, so zones in the northern and southern hemispheres are read the same way.
Daylight saving starts: the change to the larger offset
Daylight saving ends: the change to the smaller offset
Shift: the larger offset minus the smaller one
Clock time at the change: the reading on the zone's clock when the change happens.The rules behind the dates
In the United States, according to NIST, daylight time starts at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November (NIST: Daylight Saving Time).
In the United Kingdom the clocks go forward at 1 am on the last Sunday in March and back at 2 am on the last Sunday in October (GOV.UK: When do the clocks change).
Other zones have their own dates. The table shows them for the year you choose.
What this page does not show
- Years before 1970 and after 2100. The calculator covers 1970 to 2100.
- Changes that were decided after your browser's time zone data was made. A new decision may not show until the browser updates its data.
- Local exceptions inside a country. A zone name names a region, and the rules inside one country can differ.
Worked example: Europe/London, 2026
In 2026 the clocks go forward on Sunday 29 March, from 1 am to 2 am, and back on Sunday 25 October, from 2 am to 1 am.
London's offset is UTC+00:00 in standard time and UTC+01:00 in daylight time, so the shift is one hour.
| Change | Date | Clock time at the change | Offset before | Offset after |
|---|---|---|---|---|
| Daylight saving starts | 29 March 2026 | 01:00 | UTC+00:00 | UTC+01:00 |
| Daylight saving ends | 25 October 2026 | 02:00 | UTC+01:00 | UTC+00:00 |
Frequently asked questions
Which dates do the clocks change?
It depends on the zone. In the United States the change is on the second Sunday of March and the first Sunday of November, and in the United Kingdom on the last Sunday of March and of October. Choose a zone to see the dates for that place.
What does the clock time at the change mean?
It is the reading on the clock at the moment it changes. A time of 01:00 in spring means the clock jumps from 01:00 to 02:00, and a time of 02:00 in autumn means it goes back from 02:00 to 01:00.
Do all countries use daylight saving time?
No. Many zones keep the same offset all year, and the table then shows no daylight saving change. The page reports what the browser's time zone data says for the zone and year you choose.
Why might the dates be different on another device?
The dates come from the time zone data built into the browser or device. An older copy may not have a rule that a government changed recently, so its dates can differ from these.
Is the time zone I type sent anywhere?
No. The calculation runs in your browser, and the zone name you type is not stored or sent to us.
Can I see the dates for a year before 1970?
Not on this page. The calculator covers the years from 1970 to 2100 and does not show earlier changes.
Sources
- NIST: Daylight Saving Time (second Sunday of March, first Sunday of November, at 2:00 a.m.)
- GOV.UK: When do the clocks change (last Sunday of March and October, 1 am and 2 am)
- IANA Time Zone Database: the zone names and their history of local time
Figures and text last checked on Thursday, November 12, 2026.