Time Zone Calculator

Convert a specific date and time between two time zones without the Daylight Saving Time guesswork.

How to Use the Time Zone Calculator

Enter a date and time, choose the source time zone it's written in, and choose a target time zone — the converted date and time in the target zone, plus both zones' current UTC offsets, update immediately.

"EST is UTC-5" is true for exactly half the year and wrong for the other half. Eastern Time sits at UTC-5 in winter under Eastern Standard Time, then shifts to UTC-4 in summer under Eastern Daylight Time — a fixed-offset lookup has no way to know which one applies to a date typed in without also knowing the date, and that's exactly the step most naive time zone tools skip.

Eastern Time, January: UTC−05:00 (EST)
Eastern Time, July:    UTC−04:00 (EDT)

This calculator avoids that mistake by working with named IANA zones — "America/New_York," not "EST" — and asking the browser's own time zone database what the correct offset actually was for the exact date entered. That database tracks each region's real, legislated Daylight Saving rules, including regions that have changed those rules over the years, so the offset it resolves is the one that actually applied, not a guess based on the zone's most common offset.

The conversion itself never manually adds an offset to build a display string — doing that risks getting daylight saving or calendar rollover wrong at the edges. Instead, it resolves the exact moment in UTC first, then asks the target zone to format that same instant on its own terms, which is also what correctly rolls the date forward or back a day when a conversion crosses midnight.

2:30 PM in New York converts to 7:30 PM in London whether the date is in June or January — not because the offset is fixed, but because both zones happen to shift their own clocks for daylight saving at similar times of year, keeping the gap between them constant even though neither zone's individual offset is. About twenty common zones are available on each side, from UTC and the major US zones through Europe, Africa, the Middle East, South and East Asia, and Australia/New Zealand.