Worked example
Working hours overlap for the US and UK
Overlap is the hours that land inside every person’s local workday at the same moment. In mid-October, London and New York share 14:00–18:00 UK time (09:00–13:00 in New York) — four hours. Put Manila on the same call and there is no hour inside all three workdays.
Formula
Pick one clock (UTC is easiest). Convert each office’s work window, then take the intersection.
overlap = intersection of each person’s local 09:00–18:00, converted to the same clock
This example uses a mid-October weekday: London on BST (UTC+1), New York on EDT (UTC−4), Manila on PHT (UTC+8). London is five hours ahead of New York and seven hours behind Manila for most of the year. The US–UK gap drops to four hours for about a week in March and a week in late October, when only one side has changed clocks. Check the date before you send the invite.
Example: London and New York
| London workday | 09:00–18:00 BST = 08:00–17:00 UTC |
|---|---|
| New York workday | 09:00–18:00 EDT = 13:00–22:00 UTC |
| Shared window | 13:00–17:00 UTC |
| In local time | 14:00–18:00 London and 09:00–13:00 New York |
A 10:00 London standup is 05:00 in New York — before the US workday. A 10:00 New York standup is 15:00 in London, which sits inside the four-hour overlap.
Open London and New York in the overlap calculator
Add Manila
| Manila workday | 09:00–18:00 PHT = 01:00–10:00 UTC |
|---|---|
| London ∩ Manila | 08:00–10:00 UTC → 09:00–11:00 London, 16:00–18:00 Manila (2 hours). New York is 04:00–06:00. |
| New York ∩ Manila | No overlap. Manila’s workday ends at 10:00 UTC; New York’s starts at 13:00 UTC. |
| All three | Empty. No hour is 09:00–18:00 for London, New York, and Manila together. |
The fair read is not “find a time that’s fine for everyone.” It is “name who is outside their workday.” A slot inside the London–New York overlap (15:00 London / 10:00 New York) is 22:00 in Manila.
Open London, New York, and Manila
Other write-ups: SaaS pricing, fully loaded employee cost, LTV to CAC.
Cite: Do One Job — Working hours overlap for the US and UK. https://doonejob.com/working-hours-overlap/