Timezone Conversion
Coordinating meetings and calls across multiple time zones
Time zone math is simple in theory — add or subtract a fixed offset — and genuinely error-prone in practice, because the offset isn't actually fixed. Daylight saving time shifts by an hour twice a year in places that observe it, and different countries change their clocks on different dates (or not at all), which means the gap between two cities' local time can quietly change depending on the time of year. A calculation that was correct in July can be an hour off in January.
The practical fix is a tool that always uses the current, correct offset rather than a memorized fixed gap, and that lets you work backward — pick a time in one zone and see what that is everywhere else at once, rather than doing the arithmetic separately for each city.
ZoneShift is built around pinning the cities you actually coordinate with and seeing all their current times on one screen, plus a What-If mode: type a hypothetical time in any pinned zone and every other pin updates instantly, which is the actual workflow most people need when proposing a meeting time across zones.
The app
How it compares to other tools
Frequently asked questions
Why does the time difference between two cities sometimes change during the year?
Because daylight saving time (DST) shifts clocks by an hour in places that observe it, and different countries and regions start and end DST on different dates — or don't observe it at all. Two cities that are 8 hours apart for part of the year can be 7 or 9 hours apart at another point, depending on each location's DST schedule.
What's the safest way to schedule a meeting across time zones?
Use a tool that calculates the current offset live rather than relying on a memorized or previously-correct gap, and always confirm the specific date the meeting will occur on — not just "what time is it there now" but "what will the offset be on that date," since DST transitions can change it.
Is UTC the same as GMT?
They're numerically equivalent in practice (both represent the same reference time with no offset), though UTC (Coordinated Universal Time) is the modern technical standard and GMT (Greenwich Mean Time) is the older, originally astronomical definition. Most timezone offsets today are expressed relative to UTC.