Time difference = the offset of the place you are minus the offset of home, both from UTC, with daylight saving applied where it is in force. Tokyo is UTC+9 and India is UTC+5:30, so Tokyo is 3 hours 30 minutes ahead. A good time to call is when both sides are between about 8 in the morning and 9 at night. Here & Home puts two clocks and a good-time-to-call hint on your home screen.
The formula
Every time zone is an offset from UTC (Coordinated Universal Time). To find the difference between two places, subtract the offsets.
Difference = offset of where you are − offset of homeExample: Tokyo is UTC+9 and India is UTC+5:30. The difference is 9 − 5.5 = 3.5 hours. Tokyo is 3 hours 30 minutes ahead, so at 1:15 in India it is 4:45 in Tokyo. Add the difference to go from home to abroad, and subtract it to go back.
A quick table
This uses standard time, without daylight saving, and treats India as home. For other homes, subtract the offsets as above.
| Place | Offset | Compared with home in India | Good time to call |
|---|---|---|---|
| Japan (JST) | UTC+9 | +3:30 | 08:00 to 17:30 at home |
| Singapore (SGT) | UTC+8 | +2:30 | 08:00 to 18:30 at home |
| Dubai (GST) | UTC+4 | −1:30 | 09:30 to 21:00 at home |
| Germany, France, Italy (CET) | UTC+1 | −4:30 | 12:30 to 21:00 at home |
| United Kingdom (GMT) | UTC+0 | −5:30 | 13:30 to 21:00 at home |
| US East (EST) | UTC−5 | −10:30 | 18:30 to 21:00 at home |
| US West (PST) | UTC−8 | −13:30 | no overlap |
| Australia East (AEST) | UTC+10 | +4:30 | 08:00 to 16:30 at home |
A positive difference means the place is ahead of home, so its clock shows a later time.
Daylight saving: where it goes wrong
Many countries shift their clocks by an hour in summer, and they do it on different dates. The United States generally starts on the second Sunday of March and ends on the first Sunday of November. The European Union changes on the last Sunday of March and the last Sunday of October. Many countries, including India and Japan, do not change at all. For a few weeks each spring and autumn the gap between two places can change by an hour, even though neither of you has moved.
- When you plan a call in March, April, October or November, check the exact date.
- Use a clock that shows the actual local time for each place, not just a fixed difference.
- Check the zone for a city, not a country. Some large countries have several zones.
The best time to call
As a rule of thumb, a good time to call is between about 8 in the morning and 9 at night for both people. Work out your window, then see where it overlaps with theirs. The table above shows the window in home time, for example a call with Japan is comfortable from 8:00 to 17:30 at home, and a call with the US East coast works best in the evening at home. Adjust for people who sleep late or early, and for shift work.
Two clocks on your home screen
When you are not converting a price, the Here & Home widget is a dual clock: the time where you are, and the time back home, side by side, with a day and night band across both and a quiet hint when it is a good time to call. It can show analogue or digital faces, light or dark, with a transparent, glass or marble background. A weather timeline shows the temperature curve through the hours ahead.
Tips
- Set your phone to automatic time and time zone while you travel.
- Message first if you are unsure, and let people reply when it suits them.
- Schedule regular calls in each person's evening or morning, and mention the zone.
- Remember that flight times in schedules are local to each airport.
See how the same widget converts prices.
Questions people ask
How do I work out the time difference between two countries?
Subtract the UTC offset of home from the UTC offset of the place, and apply daylight saving where it is in force.
What is the time difference between India and Japan?
Japan is 3 hours 30 minutes ahead of India all year, since neither changes its clocks.
When is a good time to call home?
When it is between about 8 in the morning and 9 at night on both sides. Adjust for sleep patterns and work shifts.
Why does the time difference change in spring and autumn?
Countries start and end daylight saving on different dates, so the gap can shift by an hour for a few weeks.
Can my home screen show two clocks?
Yes. The Here & Home widget shows the time where you are and at home, with a good time to call hint and a weather timeline.
Does it need internet?
The clocks work without a signal. The weather timeline needs data to update.
Keep reading
Two clocks, one glance
Here & Home is free on Google Play. Home time, local time and the weather.
For reference. Steps and screens described here are as they appear in Here & Home, and menu names can differ between versions of Android and the app. Exchange rates and prices in examples are illustrative, and rates in Here & Home are indicative, updated periodically and not financial quotes. Emergency numbers, phrases, country facts and survival tips are general information given on a best-effort basis: check them before you travel, and do not rely on any app alone in a life-threatening emergency. Here & Home is a field companion, not a financial or emergency service. Trademarks are those of their owners and are used only to describe what the app works with.