How Time Zone Conversion Works
Every clock on Earth is anchored to UTC (Coordinated Universal Time). A time zone is just UTC plus or minus an offset: London sits at UTC+0 (UTC+1 in summer), New York at UTC−5 (UTC−4 in summer), India at a fixed UTC+5:30 and Japan at a fixed UTC+9. Converting a time means finding the exact instant it represents in the source zone, then reading that same instant with the target zone's offset.
The tricky part is daylight saving time (DST) — the US, UK, EU and Australia shift their offsets twice a year on different dates. This converter uses the IANA time zone database built into your browser, so the correct offset for the exact date you pick is applied automatically. That's why the same 3:00 PM London meeting lands at 10:00 AM New York in July but 10:00 AM becomes 9:00 AM… wait — no, it stays 10:00 AM, because both regions shift together for most of the year; only the few "mismatch weeks" in March and October/November differ. The converter gets those weeks right too.
Quick Reference — Major Cities vs IST
Where two values are shown, the difference depends on whether that city is currently observing daylight saving — the live converter above always shows the exact figure for the date you pick.
Meeting Planner — Golden Overlap Windows
| Teams | Sweet spot | What each side sees |
|---|
| India ↔ UK | 2:00–6:00 PM IST | 9:30 AM–1:30 PM London |
| India ↔ US East | 7:00–9:00 PM IST | 9:30–11:30 AM New York (summer) |
| India ↔ US West | 8:30–10:00 PM IST | 8:00–9:30 AM Los Angeles (summer) |
| India ↔ UK ↔ US East | 7:00–8:00 PM IST | 2:30 PM London · 9:30 AM New York |
| India ↔ Singapore/Tokyo | 11:00 AM–4:00 PM IST | 1:30–6:30 PM SGT · 2:30–7:30 PM JST |
| India ↔ Sydney | 9:00–11:30 AM IST | 1:30–4:00 PM Sydney (winter) |
Add all the cities to the list above and nudge the time until every row falls in working hours. Counting the days between two dates instead? Use the Date Difference Calculator, or time the call itself with the Timer & Stopwatch.
Frequently Asked Questions
How do I convert time between two time zones?
Pick the date and time, choose the source zone it belongs to, and every city on the list instantly shows the equivalent moment. Each zone's UTC offset for that exact instant is applied, so DST changes are handled automatically.
What is UTC and how do time zone offsets work?
UTC is the world's reference clock; every zone is UTC ± an offset — New York UTC−5 (−4 summer), London UTC+0 (+1 summer), India a fixed UTC+5:30, Japan a fixed UTC+9. Converting means shifting by the difference in offsets.
Does this converter handle daylight saving time (DST)?
Yes — it uses the IANA time zone database built into your browser, which knows every region's exact DST switch dates. Try a March vs December date for New York and watch the offset flip between UTC−4 and UTC−5.
What is the time difference between India and the USA?
IST is 9:30 ahead of New York in US summer, 10:30 ahead in winter; 12:30/13:30 ahead of Los Angeles. So 9:00 PM in India ≈ 11:30 AM in New York (summer).
What is the best meeting time between India, the UK and the USA?
Around 7:00–8:00 PM IST — that's 2:30–3:30 PM London and 9:30–10:30 AM New York, keeping all three sides inside normal working hours. Add the three cities above and fine-tune live.