Hong Kong is 14 hours ahead of Denver. Put the other way round: Denver is 14 hours behind Hong Kong.
Denver is UTC-6 in summer and UTC-7 in winter; Hong Kong is UTC+8 and UTC+8.
A nine-to-five in Denver and a nine-to-five in Hong Kong do not overlap at all. Somebody has to move: the nearest workable slots are early morning in one city or late evening in the other, which is the kind of thing the planner is for.
Denver changes its clocks for summer and Hong Kong does not, so there is no single answer: the gap is 14 hours for the northern summer and 15 hours for the rest of the year.
| Denver | Hong Kong |
|---|---|
| 08:00 | 22:00 |
| 09:00 | 23:00 |
| 10:00 | 00:00 next day |
| 11:00 | 01:00 next day |
| 12:00 | 02:00 next day |
| 13:00 | 03:00 next day |
| 14:00 | 04:00 next day |
| 15:00 | 05:00 next day |
| 16:00 | 06:00 next day |
| 17:00 | 07:00 next day |
| 18:00 | 08:00 next day |
This page covers one pair. TimeGap takes a list: add every city you care about, drag one marker, and every row reads the same instant on its own clock. It marks the hours you would actually take a call, finds the window where the most people are reachable, flags public holidays, and puts the time you pick straight into Outlook or Google Calendar.