Time Zone Calculators
Time zone conversion, multi-timezone meeting planning, world clock, and unix timestamp conversion — all via the browser's built-in IANA database.
Time Zone Converter
Convert a time between any two time zones using the IANA time zone database.
Meeting Planner
Find a meeting time that works across multiple time zones at once.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates.
World Clock
See the current time in major cities and time zones around the world.
Timezone conversion pages
Converting a time between two places looks like simple arithmetic — add or subtract a fixed number of hours — until Daylight Saving Time enters the picture. Roughly half the world observes some form of seasonal clock change, on schedules that genuinely don't line up between countries, which means a "fixed offset" between two cities is only fixed for part of the year.
Every tool in this category is built on the IANA Time Zone Database — the same database built into modern browsers and operating systems — specifically because it encodes each region's actual observed rules, including exactly when DST starts and ends and any historical policy changes, rather than a single unchanging offset.
Why named zones, not fixed offsets
A zone like America/New_York carries its entire rule history and future rule with it — including the fact that it's UTC−5 for part of the year and UTC−4 during Daylight Saving Time. A fixed "UTC−5" label would silently become wrong for roughly half the year. This is the single most important design decision behind the Time Zone Converter, World Clock, and Meeting Planner: work from named regions, not static offsets.
Not every place observes Daylight Saving Time, and the ones that do don't agree on when
Most of Asia, Africa, and a large share of South America don't use Daylight Saving Time at all. The US, Canada, and the EU do — but on separate schedules, changing on different Sundays each spring and autumn. That mismatch means the gap between two specific cities can genuinely change by an hour for a week or two each year, exactly during the period when only one side of the pair has changed its clocks and the other hasn't yet.
Scheduling across more than two zones is a genuinely harder problem
Converting a single time between two places is one calculation. Finding a meeting slot that works reasonably across five participants in five different zones is a different, harder problem — some combinations of zones (US West Coast and East Asia, for instance) genuinely have no fully convenient overlapping working-hours window at all. The Meeting Planner is built to surface the least-bad available option honestly in that case, rather than claiming a perfect slot exists when it doesn't.
Two computing-specific tools: Unix timestamps and the World Clock
The Unix Timestamp Converter deals with a different but related problem: translating between a plain count of seconds since January 1, 1970 (UTC) and a human-readable date — a format used constantly in log files, APIs, and databases, and one where a seconds-vs-milliseconds unit mismatch is a very common real source of dates appearing to show the 1970s. The World Clock applies the same underlying time zone data as the other tools in this category, just displaying several cities' current local time simultaneously rather than converting one specified time.
Where time zone mistakes actually cause real problems
Missed international meetings are the most visible consequence of a time zone mistake, but the underlying cause is almost always one of the two errors already described — a stale fixed-offset assumption, or forgetting that two DST-observing regions can change their clocks on different calendar dates. International logistics, customer support coverage schedules, and financial markets operating across regions all depend on getting this right consistently, which is exactly why every tool in this category works from the IANA Time Zone Database rather than a simplified, static offset table.
How these tools relate to each other under the hood
The Time Zone Converter, World Clock, and Meeting Planner share the identical underlying time zone data and conversion logic — the difference between them is purely what each does with that shared foundation, from a single pairwise conversion, to several simultaneous city clocks, to a full multi-participant scheduling search. The Unix Timestamp Converter is this category's outlier by design: rather than converting between two human-meaningful representations of time, it translates a plain machine-readable second-count into a human-readable date, more relevant to developers than to everyday scheduling, but grouped here because it's fundamentally still a time-representation problem.
A note on accuracy and data freshness
Time zone rules occasionally change by government decision — a country adjusting, adopting, or abolishing Daylight Saving Time, or shifting its standard offset. Because every tool in this category reads from the IANA Time Zone Database rather than a hardcoded table, those changes are reflected automatically whenever the underlying browser or platform's copy of that database is updated, rather than requiring this site's own tools to be manually patched for every real-world policy change.
Time zones vs. the per-country Holidays pages
It's worth distinguishing this category from the site's separate per-country Holidays section: time zone tools answer "what time is it there," a question about the clock; the Holidays pages answer "what day is observed there," a question about the calendar. A visitor scheduling an international call needs this category's tools; a visitor checking whether a specific country's offices are closed on a given date needs the Holidays pages instead.
A note on precision and rounding
Time zone offsets are occasionally non-whole-hour values (India's UTC+5:30, for instance), and every tool in this category preserves that exact offset rather than rounding to the nearest whole hour — a rounding shortcut that would silently misstate the real local time in the handful of regions that use a half-hour or 45-minute offset.
Real teams, real scheduling failures this category is built to prevent
Distributed software teams are one of the clearest real audiences for this entire category: a team split across the US, Europe, and India routinely needs to find a daily standup slot, and doing that by mentally tracking three separate offsets — one of which observes Daylight Saving Time on a US schedule, one on an EU schedule that changes on a different date, and one that never observes it at all — is exactly the kind of manual tracking that reliably produces a missed or mistimed meeting at least once a year, right around a DST transition week.
Customer support coverage is a second genuine real use case: a support team promising "24/5 coverage" across regional shifts needs to know exactly when each region's business hours actually begin and end in a shared reference zone, not an assumed fixed offset — a handoff gap or overlap of even an hour, multiplied across a year, represents either a real coverage hole or real duplicated cost.
International logistics and financial markets are a third: a shipment's promised delivery window or a market's opening bell is frequently quoted in one specific zone's local time, and converting that correctly for a customer, partner, or trader based elsewhere is a small but genuinely consequential calculation if it's gotten wrong.
The `/convert/[pair]/` pages: curated pairs vs. the general-purpose tools
Beyond the four interactive tools in this category, the site also maintains a large set of curated city and time-zone pair pages (for example, a dedicated page converting US Eastern time to India Standard Time) — each with its own worked example, current offset, and best-overlap-window specific to that exact pair, rather than requiring every visitor to run the general Time Zone Converter themselves for a handful of very commonly searched combinations. Those pages and this category's interactive tools share the identical underlying IANA time zone data; they differ only in whether the pair is pre-selected and pre-explained, or left fully general for any two zones a visitor chooses.
Frequently asked questions
Why do these tools use city names instead of UTC offsets?
Because a fixed offset silently becomes wrong across a Daylight Saving Time transition; a named zone carries its full rule history and future rule with it.
Do all countries observe Daylight Saving Time?
No — most of Asia, Africa, and much of South America don't use it at all, while the US, Canada, and the EU do, each on their own separate schedule.
What if a meeting group has no time that works for everyone?
The Meeting Planner shows the option with the fewest participants outside their working hours rather than falsely claiming a perfect match exists — some globally spread groups genuinely have no convenient overlap.
Why does a Unix timestamp sometimes convert to a date in the 1970s unexpectedly?
Almost always a seconds-vs-milliseconds mismatch — see the Unix Timestamp Converter for the full explanation.
Can the World Clock and Meeting Planner show non-whole-hour offsets correctly?
Yes — regions like India (UTC+5:30) and parts of Australia (UTC+9:30) are represented at their exact offset, not rounded to the nearest hour.
Do these tools require an internet connection to convert a time?
No — the time zone data is built into the browser itself, so conversion works entirely client-side once the page has loaded.