Tools
Timezone overlap calculator for remote teams
Two local calendars can look fine and still miss. Set each office's hours and the date. The planner finds the shared UTC block, including daylight saving.
Key takeaways
Overlap is a UTC instant
Two offices overlap when both local clocks sit inside the windows you set, at the same moment.
US East and Pakistan 9 to 5 do not meet
Pakistan is nine or ten hours ahead. A US morning against a Lahore evening is the usual fix.
Daylight saving moves the gap
The US and the UK shift. Pakistan does not. Recheck the week a DST switch lands.
The URL is the share
Cities, hours, and date live in the query string. Paste the link. Skip the screenshot.
How do I calculate timezone overlap?
- 1
Pick the two cities
Choose each office from the list, or start from a preset such as US East and Lahore.
- 2
Set local working hours
Enter the start and end each team actually sits at the desk, in that city's local time.
- 3
Choose the date
Pick the meeting day so daylight saving for that date is applied, not a generic season.
- 4
Read the purple block
Each row is that city's local clock. Blue and amber are working hours. Purple is the shared overlap. Copy the Slack line if you need to send it.
What is timezone overlap?
Timezone overlap is the stretch of clock time when two places sit inside their working hours at the same moment. It is not the offset between the two cities. New York and Lahore sit nine or ten hours apart. That gap does not tell you whether 09:00 to 17:00 on both sides ever meet. They do not.
You use this planner when two offices need a meeting both sides can attend. The usual failure is an invite that looks local and reasonable on each calendar. New York sees 09:00. Lahore sees 09:00. Those are different moments. You still get twelve people on a call with no shared hour.
Set the hours each team really sits at the desk. Read the total before you book a kickoff. If the total is zero, move a window. Zero stops a workshop that never had a room.
How does this timezone overlap calculator work?
The planner converts both windows into UTC instants and keeps only the instants that land in both. It starts at midnight in the first city on the date you picked, then walks 24 hours in 15-minute steps. A step counts only when both local clocks sit inside the hours you set. Those steps become the purple block. The total is as fine as 15 minutes.
If a window crosses midnight, hours after the start or before the end still count. Night shift is a real window. Each row is that city's local day. Purple is the same UTC block drawn at local hours, so it sits at different places on the two rows.
Do US East and Pakistan 9 to 5 overlap?
Nine to five Eastern Time and nine to five Pakistan Standard Time do not overlap. Pakistan Standard Time is UTC+5 all year. Eastern Time is UTC-5 in winter and UTC-4 in summer. The gap is nine hours in US daylight time and ten hours in US standard time.
A pattern that works: 08:00 to 12:00 in New York against 17:00 to 21:00 in Lahore. That is a US morning and a Pakistan evening. Do not pretend a full eight-hour shared day exists on this pairing unless someone is working a night shift.
US West is harder. Pacific Time sits three hours behind Eastern Time. If the product owner sits in San Francisco, use a shorter morning block or move the meeting to someone on the East Coast.
How much overlap do UK, UAE, and Lahore share?
London and Lahore share a late morning on most weekdays. In Greenwich Mean Time, 09:00 to 17:00 in London meets 09:00 to 17:00 in Pakistan for about three hours. During British Summer Time the shared block grows to about four hours.
Dubai and Abu Dhabi sit on Gulf Standard Time, UTC+4, with no daylight saving. Pakistan is one hour ahead. Two standard workdays often share six or seven hours. Riyadh is in the same neighborhood of the clock.
If you are comparing engagement models, the offshore development center guide covers how overlap hours get used for decisions.
Why does the date matter for daylight saving?
The planner uses IANA time zones and the date you pick. America/New_York and Europe/London move in spring and autumn. Asia/Karachi does not. Asia/Dubai does not. A window that works in January can shrink in April. Recheck the week a DST switch lands if you are booking a kickoff or a workshop.
The URL holds both zones, both windows, and the date. Change the date around a DST switch instead of screenshotting a winter calendar into a summer Slack thread.
How many overlap hours does an offshore team need?
You do not need eight shared hours to run an offshore software team. You need a reliable block for the work that cannot wait 24 hours: architecture calls, production incidents, and anything that needs a decision in the room. Two to four hours is a common target. The rest of the day is written status, pull requests, and implementation.
Name the overlap. Put it on the calendar as a standing window. If the only shared minute is a rushed standup, the squad will feel remote even when the clocks technically meet.
This page is a planning slice, not a calendar product. Copy the local times into Google Calendar or Outlook yourself. It does not export an .ics file. Named engineers on your standups every week is an engagement conversation. The QR generator is the sibling tool for a branded link, a vCard, or office WiFi.
Timezone overlap FAQ
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