Reviewed by Carlos Vargas, Texas Licensed Funeral Director (TFSC #119648) ·
The hours that matter are the ones you share
A family in Dallas arranging a burial in Manila, Lagos or Guatemala City has to reach registries, cemeteries and relatives whose working day may be ending as theirs begins. Calls placed at the wrong hour cost a full day each time. This helper takes the hours you can call and the hours an office says it is open, and shows where the two overlap on a particular date, in both local times.
It works from your entries only. It does not know any office’s real hours, holidays or willingness to answer, so copy the hours from the office’s own notice, and treat the result as a time to try, not an appointment.
Find the shared hours
Enter the office hours exactly as the office publishes them, in its own local time.
The controls require JavaScript.
Why the date matters: clocks change on different days
The gap between two places is not constant through the year. The U.S. National Institute of Standards and Technology explains that daylight saving time in the United States begins at 2:00 a.m. on the second Sunday of March and ends at 2:00 a.m. on the first Sunday of November, that it is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands or most of Arizona, and that time zones and daylight saving time are regulated by the U.S. Department of Transportation. Many countries never change their clocks, and those that do often change on other dates.
So a relative who is six hours ahead of Dallas in July may be seven hours ahead in December. The helper asks for a date for that reason and calculates the difference for that day instead of applying a fixed number of hours.
Where the time zone rules come from
The calculation uses the time zone data built into your browser, which follows the IANA Time Zone Database. IANA describes it as code and data representing the history of local time for many representative locations worldwide, updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets and daylight-saving rules. A government can change its rules at short notice, and a device that has not been updated may lag behind. If a result looks wrong, check the current local time of the other city before you call.
The zone list names one representative city per zone. Choose the city that shares the clock of the place you are calling; it does not have to be the same town.
Read the result
Select Calculate times after entering the date, both sets of hours and both zones.
| Line | Meaning |
|---|---|
| Your availability | The hours you entered, with the UTC offset in force that day |
| Overlap | Each period when you are free and the office hours you entered are running, shown in both local times with the weekday |
| No overlap | Your hours and the office hours do not meet on that date; try earlier or later hours |
Look at the weekday on the office’s side. Your Thursday evening can be its Friday morning, and in some countries Friday or Saturday is part of the weekend. Our business-day counter handles closures and weekends over a longer period.
Keep it practical
Recalculate when the date or either schedule changes; any edit clears the previous result. The helper script does not transmit your entries or write them to browser storage, and other services on this site follow their own privacy terms. There is nothing personal to enter here: a date, four times and two zones.
Questions about calling across time zones
- Does the helper know when a consulate or registry is open?
- No. It uses only the opening and closing times you enter. Copy them from the office’s own notice and confirm holidays with the office.
- Why do I have to enter a date?
- Because the difference between two zones can change during the year when one place changes its clocks and the other does not, or when they change on different dates.
- What if the office works a split day with a long midday break?
- Run the calculation twice, once for the morning hours and once for the afternoon hours.
