County Maps US

Tools Elevation, time and sun

Time Difference Calculator

Add the cities on a call and the tool shows the hours that work for all of them, today, with DST already accounted for.

How to use it

  1. Enter your city in the first box (your own zone is preset) and another city in the second; add up to five.
  2. Read the difference from the first city to each of the others, and the live clocks.
  3. Set the working day, 9 to 17 by default, and look for the shaded columns where every city is at work.
  4. Copy the page link: the cities and hours are kept in the address bar.

How it works

Each city is resolved to a coordinate by the Photon geocoder and then to an IANA time zone in your browser by the tz-lookup library. Every clock, offset and grid cell is computed from the browser’s Intl time zone database for the actual instant, so a city on summer time and a city on standard time are compared correctly on the day, including the weeks when the United States and Europe change their clocks on different dates.

The grid takes today in the first city, one column per hour from midnight, and writes the local hour in every other city for that same instant. A cell is shaded when that hour falls inside the working day you set; the last row marks the columns where all of them do.

Questions

Why is the difference not a whole number of hours?
Some zones sit at a half or quarter hour: India is UTC+5:30, Nepal UTC+5:45, Newfoundland UTC-3:30. The tool shows the exact difference.
Does it handle daylight saving time?
Yes, for the date shown. The difference between New York and London is 5 hours most of the year but 4 hours for a couple of weeks in March and October, and the grid reflects that.
What if there is no overlap?
The page says so. Widen the working day, for example 8 to 18, to see whether an early or late slot exists.

All map tools, free and without an account. Location data is processed in your browser and by the open geocoding services named on the sources page; nothing is stored by this site.