Time Zone Calculator: What Time Is It There?
Pick a base city and a date and time, then pick a second city to compare it to. You'll instantly see the equivalent local time there, how many hours ahead or behind it is, and whether that puts it on a different calendar day.
Times use your device's own time zone database, so daylight saving is handled automatically for every date — no live network needed.
Why time zone math trips people up
The trouble isn't the arithmetic — it's that the numbers involved keep changing. Most of the world's clocks aren't simply UTC±N: many places shift by an hour for daylight saving, and not on the same dates as each other (the US and Europe change on different weekends, and much of Asia, Africa and most of the tropics don't observe it at all). So the gap between two cities can quietly change by an hour depending on the date you pick, not just the cities.
On top of that, a handful of zones aren't offset by a whole hour at all — India is UTC+5:30 and Nepal is UTC+5:45 — and converting across the International Date Line can push a time onto the next or previous calendar day, not just a different hour.
How this calculator gets daylight saving right
Rather than keep its own table of UTC offsets (which would drift out of date and get daylight saving wrong for half the year), this calculator reads your device's built-in IANA time zone database — the same one your phone and computer already use to show the correct time wherever you are. For the exact date you enter, it looks up whether each city was observing daylight saving on that date and applies the right offset automatically, rather than assuming today's rules apply all year round.
Reading the day/night bar
Each city gets a 24-hour strip with a marker showing where its clock currently sits, shaded dark for night and light for day. It's a quick way to check you're not about to call someone at 3 AM their time before you even look at the numbers.
Frequently asked questions
- Why isn't the gap between two cities always the same number of hours?
- Because daylight saving doesn't start and end on the same date everywhere. The US, for example, changes clocks about two to three weeks before most of Europe does, so a city pair's difference can shift by an hour for part of spring and autumn each year.
- What does the +1 day or −1 day badge mean?
- It means that at the exact moment shown, the other city's calendar date is one day ahead or behind the base city's — common when converting across time zones near midnight or across the International Date Line.
- Does this handle daylight saving for past and future dates, not just today?
- Yes. It looks up the rules for the specific date you enter using the time zone database, so a date in July and a date in January for the same city can correctly show different offsets.
- Why are some time zones 30 or 45 minutes off the hour?
- A few countries chose an offset that isn't a whole hour from UTC, usually to sit between two neighbours — India (UTC+5:30), Nepal (UTC+5:45) and parts of Australia (UTC+9:30) are the best-known examples.
- Where does the time zone data come from?
- From the IANA Time Zone Database, the standard reference most computers, phones and software use, already built into your browser — no data is sent anywhere to look it up.