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Time & Dates

Time Zone Converter

See what time it is in another time zone for any date and time, with daylight saving time worked out for that exact day.

Level: Grades 3–4

Printable worksheet

Time Zone Converter

Inputs

The date matters: daylight saving time depends on it.

Choose a date.

Result

Calculating…

Test yourself

20 quick questions built from this calculator's formula: work out results, predict what happens when an input changes, and work backward from an answer. Every answer comes with the working.

What this calculator does

Find out what time it is somewhere else when it's a certain time where you are. That's the question behind every call or flight across time zones. The answer depends on the date as well as the places. Many places move their clocks for daylight saving time, and they don't all move on the same day. For a few weeks each spring and fall, New York and London are four hours apart instead of five.

You enter a date, a time and a starting zone. The converter works out the exact moment that means, then reads the clock in the other zone at that moment. The time differences and daylight saving rules come from the time zone data built into your browser. Your device uses the same data for its own clock, so nothing is typed in by hand. A table shows the same moment in every listed zone.

Where it's used

Why this math matters outside the classroom:

  • Video calls. A 2:00 p.m. call in New York is 11:00 a.m. in Los Angeles, three hours earlier.
  • International flights. Travelers convert an arrival time to their home time zone to plan calls with family.
  • Remote teams. Managers find a meeting hour that falls inside working hours for staff in several cities.
  • Live events. Viewers convert a broadcast start time from the host city into their own local time.

How to use it

  1. Pick the date. It starts at today. Change it for a future meeting, because daylight saving may be different by then.
  2. Enter the local time in the starting zone.
  3. Choose the zone you're converting from and the zone you're converting to. Each zone is listed by a major city.
  4. Read the converted time and date, the difference in hours, and each zone's UTC offset (how far its clock is from world time). The table lists the same moment in every zone.

What the inputs mean

Date
The calendar date in the starting zone. It decides whether daylight saving time applies on each side.
Time
The local clock time in the starting zone, on a 24-hour clock. If you pick a time that's skipped when clocks spring forward, you'll see an error.
From time zone
The zone the time is in. Each city stands for its whole zone: New York covers US Eastern time, Chicago US Central, and so on.
To time zone
The zone you want the time in. UTC is the same as Zulu time in military and aviation use.

Formula and method

UTC = local time − offset of the starting zone
target time = UTC + offset of the target zone
difference = target offset − starting offset

UTC (Coordinated Universal Time) is the world's reference clock. A zone's offset is how many hours its clocks are ahead of or behind UTC. The target zone is the one you're converting to.

So every zone's clock is UTC plus its offset. New York is UTC−5 in winter and UTC−4 in summer. Berlin is UTC+1 and UTC+2. India is UTC+5:30 all year. Taking away the starting zone's offset turns the local time into UTC. Adding the target zone's offset turns UTC into the time there.

The offsets are looked up for the exact moment you're converting. That's what makes daylight saving come out right. On the night clocks spring forward, one hour of local time never happens. On the night they fall back, one hour happens twice. The converter shows a skipped time as an error. For a time that happens twice, it uses the first one and tells you so.

Worked example

A call is set for 3:00 PM on Friday, March 20, 2026 in New York. What time is that in Berlin?

  1. New York switched to daylight saving time on March 8, so its offset is UTC−4.
  2. UTC = 15:00 − (−4 h) = 19:00 UTC.
  3. Europe does not switch until March 29, so Berlin is still on UTC+1.
  4. Berlin = 19:00 + 1 h = 20:00.

Result: The call is at 8:00 PM, Fri, Mar 20, 2026 in Berlin. The gap is 5 hours that week, not the usual 6. That's because the US changed its clocks three weeks before Europe.

Understanding the result

"Ahead by" is the target zone's offset minus the starting zone's. A positive number means the clocks there are later. A negative number means they're earlier. Some zones are off by half or quarter hours, such as India (+5:30) and Nepal (+5:45).

The day result tells you when the converted time falls on a different date. Evening in the Americas is often the next morning in Asia and Australia.

The working shows whether daylight saving time applies. "In effect" means the zone is on its summer time. "Not observed" is for zones such as Phoenix, Tokyo or UTC that keep one offset all year.

Assumptions and limitations

  • Each city stands for its whole zone, as set out in the IANA time zone database (the shared list of the world's time zones).
  • Offsets and rule changes are whatever your browser's built-in time zone data contains.
  • Only the listed zones are offered. Places that share a zone with a listed city can use that city.
  • Sometimes a government changes its daylight saving rules at short notice. Results for dates after the change are only right once your browser's time zone data is updated.
  • Dates from 1970 to 2100 are supported. Time zone history before 1970 is less reliable.

Frequently asked questions

What is the difference between UTC, GMT and Zulu time?

For everyday use they show the same time. UTC is the world's reference clock, and Zulu is its name in military and aviation use. GMT is the UK's winter time, which matches UTC. The difference is that London switches to British Summer Time (UTC+1) in summer, while UTC never changes.

Why is the gap between the US and Europe sometimes an hour shorter?

The US starts daylight saving time on the second Sunday of March and ends it on the first Sunday of November. The EU and UK change on the last Sundays of March and October. In the weeks between, one side has changed and the other hasn't. So the usual gap shrinks by an hour.

What happens if I enter a time that doesn't exist?

When clocks spring forward, say from 2:00 straight to 3:00, times such as 2:30 never happen that night. The converter explains this instead of guessing. When clocks fall back, a time such as 1:30 happens twice. The converter uses the first one and notes that the second is an hour later.

Do all countries use daylight saving time?

No. Most of Asia, Africa and South America keep one offset all year, and so do Arizona and Hawaii in the US. South of the equator, places that do use it, such as Sydney and Auckland, move their clocks forward around October and back around April.

How this calculator is checked

Method: UTC offsets from the IANA time-zone database as exposed by the ECMAScript Intl API (Intl.DateTimeFormat); local → UTC → local conversion at the resolved instant. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.

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