Time zone overlap calculator
Pick two time zones and each side's work hours. The calculator shows the hours you're both working on the date you choose, with daylight saving applied, and draws them on a 24-hour bar. Then copy a link that opens in the other person's time zone. For example, India and London share 4h 30m of a 9-to-6 day from Mar 29 to Oct 24, 2026.
4h 30m of shared work time
- 1:30 PM to 6:00 PM IST = 9:00 AM to 1:30 PM BST
The link shows these hours on two clocks and opens in the other person's time zone.
How many work hours overlap between common time zones?
A 9 AM to 6 PM day on both sides, for today, with daylight saving applied. Each pair links to its full converter.
| Zones | Shared | When, on the first clock |
|---|---|---|
| India and London | 4h 30m | 1:30 PM to 6:00 PM IST |
| India and Berlin | 5h 30m | 12:30 PM to 6:00 PM IST |
| India and New York | None | 30m apart |
| India and San Francisco | None | 2h 30m apart |
| India and Sydney | 3h 30m | 9:00 AM to 12:30 PM IST |
| New York and London | 4h | 9:00 AM to 1:00 PM EDT |
| New York and Berlin | 3h | 9:00 AM to 12:00 PM EDT |
| New York and San Francisco | 6h | 12:00 PM to 6:00 PM EDT |
| London and San Francisco | 1h | 5:00 PM to 6:00 PM BST |
| Manila and New York | None | 3h apart |
| Sydney and San Francisco | 3h | 9:00 AM to 12:00 PM AEDT |
How do you find overlapping work hours?
Put their work day on your clock, then keep only the part that sits inside your own work day. The catch is the date. A gap can grow or shrink by an hour from one month to the next, because countries move their clocks on different days and some never do. The calculator turns both work days into real moments for the date you pick, so the answer is right for that day, not just most of the year.
What if your work hours don't overlap?
The calculator tells you how far apart the two days are. From there you have three options. One side starts early or stays late by that much. You take turns, so the same person isn't always on the late call. Or you share the hours you're free outside work: mark them on a clock and send a link that opens in their time zone.
Questions
The hours when people in two time zones are both at work. India and London share 4h 30m of a 9 AM to 6 PM day from Mar 29 to Oct 24, 2026, and 3h 30m the rest of the year.
None, for a 9 AM to 6 PM day on both sides. New York's day starts 30m to 1h 30m after India's ends, so one side has to stay late or start early.
4h of a 9-to-6 day, 2:00 PM to 6:00 PM London time, for most of the year. It changes for a few weeks when one side has moved its clocks and the other hasn't.
Yes, by an hour when one side moves its clocks and the other doesn't. For example, London and New York share 5h on Mar 21, 2027, when only the US has switched, and 4h once London switches on Mar 28, 2027. Pick the exact date in the calculator to get the right hours.
Yes. Set an end time earlier than the start, like 10 PM to 6 AM, and the shift runs past midnight.
Yes. Copy link sends the shared hours as two clocks, and the link opens in the other person's time zone. No sign-up on either side.
Working from India?
Each of these has work hours in IST, the best time to call and an hour-by-hour table: India time to US time, India time to Canada time, India time to Europe time, India time to Australia time.
How this page is made: every time here is computed from the IANA time zone database for the date shown, the same data your phone clock uses. Checked October 15, 2026. Spot a wrong time? Tell us.