Meeting planners & scheduling
Business hours intersection
When are all the offices open at once? Pick your cities and a workday, and get the exact overlapping window — spelled out in every local time and in your own.
How to use the business hours intersection
Pick the two locations
Choose the offices, markets or teams whose hours you need to compare.
Set each side's working day
Business hours vary by country and industry — a 9-to-6 in one place against an 8-to-4 in another produces a different window than assuming both run 9 to 5.
Read the intersection
The result is the exact window where both are open, given in both local times, with its total length.
Act on the length
Anything under about two hours needs protecting: that is when calls, escalations and handovers have to happen, so it should not be filled with routine meetings.
Where two business days actually overlap
The overlap between two offices is often much smaller than the offset suggests. London and New York are five hours apart and share roughly three hours of standard business day. London and Singapore are seven or eight apart and share barely one. Beyond about nine hours of separation there is usually no overlap at all inside conventional hours, and someone has to move.
Local conventions matter more than people expect. The working day starts and ends at genuinely different times across countries, lunch is a long midday break in some places and a desk sandwich in others, and the working week itself differs — Friday and Saturday are the weekend in much of the Gulf, so a Friday deadline means something different there than in Europe.
The practical consequence is about promises rather than meetings. If your support is in one zone and your customer is in another with a one-hour overlap, a "same business day" response effectively means the next day for them. Knowing the real intersection lets you write commitments you can keep.
Because the window is computed from live zone data, it also moves with daylight saving. A three-hour overlap in July can be two in November when one side changes its clocks and the other does not.
When you'd reach for it
Writing an SLA
Base a response-time promise on the hours you and the customer are genuinely both open.
Support coverage
Work out whether a region needs local staffing or can be covered from an existing office.
Vendor coordination
Know the window in which a supplier can actually answer before you commit to a timeline.
Cross-border finance
Settlement and confirmation calls have to land inside both banking days.
Choosing an outsourcing region
Compare candidate locations by how much of your working day they overlap.
Setting escalation policy
Define who is paged out-of-hours based on real coverage rather than an org chart.
Questions & answers
- How is the overlap calculated?
- Each city's workday is turned into an absolute time window for today, then intersected. The result is the span when every office is simultaneously open, shown in each local time and in yours.
- Why is there sometimes no overlap?
- Cities far apart — say Los Angeles and Singapore — may have no shared 9-to-5. Widening the workday or removing the most distant office usually reveals a window.
- Can I change the office hours?
- Yes. The open and close sliders set a common workday applied to every city.