Core hours that actually work across time zones
A practical way to define shared hours without burning out your earliest or latest teammates. —
Most global teams say they have "core hours," but few can explain how they chose them or why they are fair. The result is a vague window that drifts every season, makes some people stay late all the time, and still does not help people know when they can reach each other.
Here is a simple way to set core hours that actually hold up.
1) Start with reality, not ideals
Ask each teammate for the hours they can reliably be online. Not their aspirational 9 to 5, but the hours they are actually available most days. Parents, night owls, early risers, and on call rotations all shape real availability.
When you map those hours side by side, you can see the overlap that exists today, not the overlap you wish existed.
2) Define the overlap band, then narrow it
Look for the widest overlap across the people who must meet live each week. If you have to include everyone, you can still choose a smaller band for critical decisions and reserve the wider band for optional sessions.
Example:
- Wide overlap: 2.5 hours that technically fit everyone
- Core overlap: 90 minutes reserved for decisions, pairing, or live reviews
That smaller band becomes your real core hours. The wider band is a backup.
3) Make the burden visible
If your overlap places one person at 7am and another at 10pm, do not ignore it. Write it down. Make it visible to the team. You are acknowledging a cost, and that keeps everyone honest about how much live time you consume.
If you cannot shrink the pain, rotate it. Use a monthly rotation so the early and late slots move across regions instead of sticking to the same people forever.
4) Protect the window with a simple rule
Core hours are for:
- decisions
- ambiguous problems
- moments where tone matters
Everything else goes async. If people start scheduling status updates in the core window, it becomes a tax instead of a benefit.
5) Revalidate twice a year
Daylight saving shifts will quietly break your agreement. Put a reminder on your calendar to recheck the overlap when the US or EU changes clocks.
If the team changes, update the window the same day and reshare the source of truth.
The easy part: seeing it live
If you want to do this in under a minute, create a shared board in Timezoners and add each teammate's working hours. You can see the overlap instantly and adjust without mental math. The live view on timezoners.com (also available at timezones.com) makes it clear which hours are reasonable and which are not, so your core hours feel fair and predictable.