Meeting Time Calculator
Common Overlap Windows — Quick Reference
| Timezones | Best Window (ET) | Best Window (GMT) | Notes |
|---|---|---|---|
| All US Timezones | 10AM–3PM ET | 3PM–8PM GMT | Comfortable for all 4 US zones |
| US East + London | 9AM–1PM ET | 2PM–6PM GMT | Standard transatlantic window |
| US East + Europe (CET) | 9AM–12PM ET | 3PM–6PM CET | Common US-EU enterprise window |
| US West + London | 9AM–12PM PT | 5PM–8PM GMT | Tight overlap — schedule early |
| US East + India (IST) | 8:30AM ET | 6:30PM IST | Very limited — 1 slot only |
| US West + Singapore/HK | 8–10AM PT | 11PM–1AM SGT | One side always sacrifices |
| US + Australia (AEST) | 7–9AM ET | 9–11PM AEST | Rotate — no good window |
Rotate Sacrifice
When no good overlap exists, rotate who takes the inconvenient slot. Track it — one team shouldn't always be on at 7AM or 8PM.
Async First
For teams 10+ hours apart, Loom video updates + Slack threads often work better than forced synchronous meetings.
Tue-Thu is Best
Tuesday-Thursday are the global peak productivity days. Avoid Monday morning and Friday afternoon for your most important cross-timezone meetings.
Use UTC References
Say "3PM UTC" instead of "3PM ET" for international teams. UTC doesn't shift with daylight saving and eliminates confusion during spring/fall transitions.
⚠️ Times use standard UTC offsets. Daylight Saving Time shifts are not automatically applied — verify at timeanddate.com during March/November DST transitions.
Frequently Asked Questions
For US Eastern and UK/Europe: 9AM-12PM ET (2PM-5PM GMT, 3PM-6PM CET) is the standard window. This falls within business hours for all US timezones and European offices. Avoid scheduling after 1PM ET — it becomes late evening in Central Europe. The 10AM-11AM ET slot is considered the global optimum: late enough for West Coast (7AM PT) and early enough for Europe before end-of-day.
US to Asia Pacific has no comfortable mutual overlap. US EST to Singapore: 13 hours apart. US PST to Tokyo: 17 hours apart. Best approach: (1) Rotate meeting times so burden is shared equally. (2) Keep synchronous meetings for decisions only — use async for updates. (3) Record all meetings and share summaries. (4) If regular standup is needed, use Geekbot or Standuply for async standups that don't require a live call.
Best tools: Calendly (book meetings with timezone-aware availability), World Time Buddy (worldtimebuddy.com — visual timezone overlap tool), When2meet (anonymous availability polling), Doodle (scheduling polls), and TimeZoneRocket. Google Calendar's "Find a time" feature also works well for meetings within an organization. For asynchronous scheduling across many timezones, use Loom for video messages or structured update channels in Slack.
The golden overlap window for US-based teams: 9 AM - 12 PM Pacific (12 PM - 3 PM Eastern) covers all US time zones during business hours. For US-Europe overlap: 8-10 AM Eastern covers Central European afternoon. For US-Asia overlap: 7-9 AM Pacific is early evening Asia. The key rule: find the window where no participant is outside 8 AM - 6 PM local time, then prioritize mid-morning (people are focused but not yet in afternoon fatigue).
Generally yes. Monday mornings: people are catching up on email, planning their week, and are less prepared for collaborative discussion. Friday afternoons: attention is low and any follow-up commitments are easily forgotten over the weekend. Research from Doodle and Harvard Business Review both suggest mid-week (Tuesday-Thursday), mid-morning (10-11 AM local) as the highest-focus, highest-attendance window. Schedule important decisions in that window.
Accept that someone will always be inconvenienced -- the goal is to rotate the burden fairly. Keep a meeting rotation log so the 6 AM participant this week gets a better slot next time. For recurring meetings with severe time zone conflicts, consider async alternatives: a recorded Loom video with structured response deadline often accomplishes what a meeting would without requiring simultaneous presence. If the meeting is essential, pick the earliest reasonable local time for participants on the majority timezone.