Time Zone Calculator

The time zone calculator converts a single moment in time from one place into the local clock time of dozens of cities around the world at once. Type the time you have in mind, choose the zone it belongs to, and the tool instantly tells you what that same instant reads on the clock in Mumbai, New York, London, Dubai, Singapore, Tokyo, Sydney and more. It also runs a live world clock so you can see the current time everywhere right now. It is built for anyone who works, studies or has family across borders: Indian professionals on calls with US or UK teams, freelancers serving overseas clients, students attending foreign webinars, NRIs phoning home, and travellers planning arrivals.

How time zones and UTC offsets work

Every time zone is defined as an offset from UTC (Coordinated Universal Time), the global reference clock that replaced GMT. An offset of UTC+5:30means the local clock runs 5 hours and 30 minutes ahead of UTC; UTC-5means 5 hours behind. India uses a single zone for the whole country, India Standard Time (IST) = UTC+5:30, with no daylight saving. To convert a time between any two zones you simply add the difference of their offsets. The general rule is: target time = source time + (target offset − source offset). If the result crosses midnight you also move a calendar day forward or back, which is why the tool shows a "+1 day" or "−1 day" tag where it applies.

Converting meeting times step by step

First decide the anchor: the time and zone you already know. Enter it as the source. Read off the converted time for each city you need. For a recurring meeting, pick a slot that lands inside everyone's working day — generally 7 AM to 8 PM local. From India, the most comfortable overlap with the US is early evening IST (which is morning for the US), and with the UK it is afternoon IST (late morning in London).

Worked example: IST to US and UK

Suppose a Bengaluru team wants to meet at 6:30 PM IST. IST is UTC+5:30, so that instant is 1:00 PM UTC (6:30 PM minus 5:30). London (UTC+0, ignoring summer time) reads 1:00 PM — a workable lunchtime call. New York on Eastern Standard Time (UTC-5) reads 8:00 AM (1:00 PM UTC minus 5 hours), a fine start to the US workday. So 6:30 PM in India equals 1:00 PM in London and 8:00 AM in New York. Reverse the logic to plan from the other side: a 9:00 AM EST US standup is 9:00 AM + 5:00 (to UTC) + 5:30 (to IST) = 7:30 PM IST.

A note on Daylight Saving Time (DST)

Many countries shift their clocks forward by one hour in spring and back in autumn to make better use of evening daylight. During US and European summer time, those zones are effectively one hour closer to India — for example New York moves from UTC-5 to UTC-4, so the gap with IST shrinks by an hour. This calculator uses standard (non-DST) offsets for clarity and consistency, so during a country's DST window its real local time can be one hour ahead of what is shown. India never observes DST, so IST is constant year-round.

Tips

• Always confirm whether the other country is currently on summer time before a critical call, and add one hour to that side's result if it is.
• When emailing across zones, write times with the zone label (e.g. "3 PM IST") so there is no ambiguity.
• For audiences spread very wide, look for a slot that is merely tolerable for everyone rather than ideal for one group.
• Use the live world clock to sanity-check a conversion against the current real time.

Common mistakes

• Forgetting the half-hour in IST and treating India as UTC+5 or UTC+6 — it is exactly UTC+5:30.
• Ignoring the day change: a late-night time in India can be the previous day's afternoon in the Americas.
• Adding the offset in the wrong direction — going east of UTC you add hours, going west you subtract.
• Assuming a fixed gap with the US or UK all year, when DST changes that gap by an hour for several months.