Multi-Timezone Meeting Planner
How it works
Scheduling meetings across multiple time zones is a painful but common problem for remote teams. The Multi-Timezone Meeting Planner takes a list of time zones and a target meeting time (or finds optimal overlap automatically), displaying the corresponding local time in each zone and highlighting business hours overlap.
**The core problem: time zone complexity** The world has 39+ distinct UTC offsets (not just the intuitive 24), ranging from UTC−12:00 to UTC+14:00. India is UTC+5:30 (not a whole-hour offset). Nepal is UTC+5:45. Some regions observe Daylight Saving Time (DST); others don't. The US Eastern time zone is UTC−5 in winter (EST) but UTC−4 in summer (EDT) — a different abbreviation and offset. The planner uses the IANA time zone database (the authoritative global record of every historical and current time zone transition) to correctly handle all offsets and DST rules.
**Finding overlap** For a team spanning New York, London, and Singapore: New York business hours (9am–5pm ET) overlap with London business hours (9am–5pm GMT) for 5 hours (2pm–5pm London = 9am–12pm New York). Singapore (GMT+8) business hours overlap with London for 1 hour (9am–10am Singapore = 1am–2am London — barely usable). Finding any three-way overlap requires the planner.
**UTC offsets by region** Americas: UTC−12 to UTC−4. Europe/Africa: UTC−1 to UTC+3. Asia/Pacific: UTC+5:30 to UTC+14.
**DST awareness** DST transitions typically happen in spring and autumn — but on different dates in different countries. The US and EU transition on different Sundays; Australia transitions in October/April (opposite hemispheres). A meeting "at 3pm your time" can shift by an hour after a DST transition in one participant's country.
Privacy: all scheduling logic runs in the browser. No meeting details or email addresses are transmitted.
Frequently Asked Questions
- India Standard Time (IST) was set to UTC+5:30 in 1906 as a compromise for a country spanning two natural time zones (UTC+5 in the west, UTC+6 in the east). Rather than creating two domestic time zones (which would complicate rail timetables, government functions, and broadcast scheduling across a large country), India chose a single time zone at the geographic midpoint. This is also why Nepal is UTC+5:45 (a 15-minute offset) — Nepal wanted a distinct time from both India and China as a matter of national identity.
- Most countries near the equator (where seasonal day-length variation is minimal) do not observe DST: all of Africa except Mauritius and the Canary Islands; most of Asia (India, China, Japan, South Korea, Thailand, Vietnam); tropical South America (Brazil dropped DST in 2019). In temperate regions, some have abolished it: Russia dropped DST in 2014 (stays on permanent 'summer time'). The US, EU, UK, Canada, Australia, and New Zealand still observe DST. The EU planned to abolish DST by 2021 but implementation was delayed indefinitely due to political disagreement over which permanent time to choose.
- Baker Island (US Minor Outlying Islands) is at UTC−12:00; Line Islands of Kiribati are at UTC+14:00 — a 26-hour difference. This means there can be a 2-day difference: when it's Monday morning in Baker Island, it's still Sunday in UTC−12 but already Tuesday in UTC+14. This is why the International Date Line zigzags around Pacific island nations — Kiribati moved to UTC+14 in 1995 to keep the entire nation in the same date, even though it geographically straddles the ±180° meridian.
- New York (ET): UTC−5 winter / UTC−4 summer. London (GMT/BST): UTC±0 winter / UTC+1 summer. Singapore (SGT): UTC+8 year-round. In winter: New York 9am = London 2pm = Singapore 10pm. The only practical overlap for all three: London afternoons (2–5pm GMT) = New York mornings (9am–12pm ET) = Singapore evenings (10pm–1am SGT) — which is after business hours in Singapore. In summer, the window shifts one hour. There is no time that is simultaneously business hours in all three cities; any meeting requires someone outside normal hours.