Convert time between any two time zones. DST-aware, shows current local time, updated in real time.
This free time zone converter converts time between any two of 400+ world time zones — accurately, DST-aware, and in real time. Whether you're scheduling a client meeting between London and New York, figuring out when a live stream starts in your local time, planning a call with family in Pakistan while you're in the UK, or simply checking what time it is right now in Tokyo, the tool gives you an instant, reliable answer with the current UTC offset clearly displayed.
Time zone conversion sounds simple until you actually need it under pressure — on your phone before a Zoom call, trying to figure out if 9 AM PST is a reasonable ask for your team member in Karachi. The tool shows you both times side by side with the date clearly displayed, because crossing midnight is the most common source of scheduling errors. A meeting at 11 PM EST is 9 AM the next day in Pakistan — easy to miss without a clear date label.
The live world clock at the bottom of the tool shows current local times for 8 major cities in real time, updating every second. It's useful as a quick reference when you don't have a specific conversion in mind but want to know the rough time in different regions before choosing a meeting window.
The datetime field defaults to right now — use it as-is to see what the current time is in another city. Or pick any future date and time for scheduling: click the field and use the date/time picker to select the exact moment you're planning for. This is where the DST-awareness matters most — a meeting scheduled for March 15th may have different offsets than the same meeting on December 15th if one location observes DST and the other doesn't.
Choose the time zone the input time is in — your local time zone, or the time zone of the person scheduling the meeting. The dropdown is organised by region and shows city names with their UTC offsets. If you're not sure of your exact time zone, your device's system clock can tell you, or use the closest major city in your region.
Choose the time zone you want to convert into — the location of your meeting participant, your destination city, or the broadcast origin. The swap button (⇄) reverses the two zones instantly, useful for quickly checking the conversion in both directions without re-selecting from the dropdown.
Both times display side by side with the full date and UTC offset shown beneath each. The time difference between the two zones is shown as a badge between them. Always check the date — many inter-continental meeting times cross midnight, meaning the target time falls on a different calendar day from the source time.
The dropdown covers all major world cities and time zones using the IANA time zone database — the same database used by operating systems, browsers, and programming languages worldwide. Whether you need UTC, EST, PST, IST, PKT, GST, JST, AEST, or any other zone, it's in the list, organised by region for easy navigation.
Daylight Saving Time changes UTC offsets twice a year for observing regions. This tool uses your browser's built-in Intl API, which applies current DST rules for each location on the specific date you're converting. A conversion for June 15th automatically accounts for summer time in the US and EU; a December 15th conversion uses winter offsets. No manual DST adjustment needed.
Eight major cities update in real time every second — showing the current hour, minute, and second in each location. The world clock updates without page refresh, giving you a genuine live view of current times globally. Useful for a quick sense of business hours in different regions before scheduling.
One click on the swap button reverses the source and target zones without re-selecting from dropdowns. If you convert New York → London and want to check London → New York, the swap does it in one tap. Particularly useful when checking whether a proposed meeting time is reasonable from both sides.
When the converted time falls on a different calendar day, the full date is displayed prominently beneath the converted time. This prevents the most common scheduling mistake: booking a call at "9 AM tomorrow" not realising that across 13 time zones, "tomorrow" is actually two days away from the source date.
Fully responsive on iPhone, Android, tablet, and desktop. The native datetime picker on mobile makes entering times fast and accurate without typing. No app to install and no registration required — open the page in any browser and convert immediately.
This table covers the most searched time zones globally. Note that offsets marked with * change during Daylight Saving Time in the indicated months.
| City / Region | Time Zone Name | Standard Offset | DST Offset | DST Period |
|---|---|---|---|---|
| London, UK | GMT / BST | UTC+0 | UTC+1 | Late Mar – Late Oct |
| New York, USA | EST / EDT | UTC−5 | UTC−4 | 2nd Sun Mar – 1st Sun Nov |
| Chicago, USA | CST / CDT | UTC−6 | UTC−5 | 2nd Sun Mar – 1st Sun Nov |
| Denver, USA | MST / MDT | UTC−7 | UTC−6 | 2nd Sun Mar – 1st Sun Nov |
| Los Angeles, USA | PST / PDT | UTC−8 | UTC−7 | 2nd Sun Mar – 1st Sun Nov |
| Toronto / Montreal | EST / EDT | UTC−5 | UTC−4 | 2nd Sun Mar – 1st Sun Nov |
| Paris / Berlin | CET / CEST | UTC+1 | UTC+2 | Last Sun Mar – Last Sun Oct |
| Dubai, UAE | GST | UTC+4 | No DST | — |
| Karachi, Pakistan | PKT | UTC+5 | No DST | — |
| Mumbai / Delhi, India | IST | UTC+5:30 | No DST | — |
| Dhaka, Bangladesh | BST | UTC+6 | No DST | — |
| Bangkok, Thailand | ICT | UTC+7 | No DST | — |
| Singapore / KL | SGT / MYT | UTC+8 | No DST | — |
| Beijing / Shanghai | CST | UTC+8 | No DST | — |
| Tokyo, Japan | JST | UTC+9 | No DST | — |
| Sydney, Australia | AEST / AEDT | UTC+10 | UTC+11 | 1st Sun Oct – 1st Sun Apr |
| Auckland, NZ | NZST / NZDT | UTC+12 | UTC+13 | Last Sun Sep – 1st Sun Apr |
Before the 19th century, every city kept its own local solar time — when the sun was highest in the sky, it was noon. This worked fine when travel was slow, but the arrival of railways created a practical problem: railway timetables required consistent time across large distances, and a train leaving one city needed to arrive at a known time in another. Britain adopted the first national standardised time — "Railway Time" based on Greenwich Mean Time — in 1847. The US and Canada adopted standardised time zones in 1883, when the major railroads synchronised their schedules to four continental time zones.
International standardisation came at the International Meridian Conference in Washington DC in 1884, where 25 nations agreed to adopt Greenwich as the prime meridian (0° longitude) and establish 24 time zones radiating from it. This system, with many modifications for political and geographical practicality, is essentially what we use today.
UTC (Coordinated Universal Time) is the primary time standard used globally for technical, scientific, aviation, and internet purposes. It is maintained by the Bureau International des Poids et Mesures (BIPM) using a weighted average of approximately 400 atomic clocks distributed across 70 national laboratories worldwide. UTC is synchronised to within 0.9 seconds of UT1 (astronomical time based on Earth's rotation) by the periodic insertion of leap seconds.
All world time zones are defined as offsets from UTC — for example, New York's Eastern Standard Time is UTC−5 (5 hours behind UTC), and India Standard Time is UTC+5:30 (5 hours and 30 minutes ahead of UTC). When you convert between time zones, you're essentially converting both to UTC and then to the target zone. This calculator does that arithmetic automatically, correctly accounting for DST offsets on the specific date entered.
Daylight Saving Time (DST) was first widely adopted during World War I as an energy conservation measure — shifting an hour of daylight from the underused morning to the evening when people are active. The modern version, in the form most countries observe it, was driven by energy saving arguments that have since been debated extensively in the research literature, with mixed findings about actual energy impact.
DST creates significant complexity for time zone conversion because it changes UTC offsets twice per year for observing regions, and the transition dates differ between countries. The United States transitions on the second Sunday of March and the first Sunday of November. The European Union transitions on the last Sunday of March and the last Sunday of October. This means there's a window each year — typically 1–3 weeks depending on direction — where the US-Europe time difference is one hour different from the rest of the year. During those windows, manually calculated conversions from memory are likely to be wrong.
Several major countries do not observe DST at all: Japan, China, India, most of South Asia, most of Africa, and several others maintain consistent UTC offsets year-round. When converting between a DST-observing and a non-observing location, the time difference changes twice a year. This tool handles all of it automatically using the IANA time zone database that encodes the DST rules for every jurisdiction.
The Internet Assigned Numbers Authority (IANA) maintains the authoritative database of world time zones — officially called the "tz database" or "Olson database" (named after Arthur David Olson, who maintained it for decades). The IANA tz database records the current and historical UTC offsets, DST transition rules, and transition history for every time zone on Earth. It is updated multiple times per year as countries change their DST rules, adjust their UTC offsets, or create new time zones following political changes.
The tz database is the time zone standard used by operating systems (Linux, macOS, iOS, Android), programming languages (Python, JavaScript, Java), databases (PostgreSQL, MySQL), and — through the browser's Intl API — this time zone converter. When JavaScript's Intl.DateTimeFormat calculates the time in "Asia/Karachi" or "America/New_York" on a specific date, it's using the tz database rules for those locations.
The growth of remote work has made time zone management a daily challenge for millions of workers. A product team distributed across San Francisco, London, and Bangalore cannot schedule any meeting without a time zone converter — or at minimum, a deep understanding of the relevant offsets. The San Francisco–London window for reasonable meeting hours is roughly 9 AM–11 AM PDT (5 PM–7 PM BST). Adding Bangalore (IST, UTC+5:30) to that same meeting means someone is always outside comfortable working hours, which is why understanding the exact times matters for making an informed scheduling decision.
Many remote teams adopt a "UTC first" culture — all meeting times, deadlines, and scheduling communications are expressed in UTC with local time in parentheses. This eliminates DST-related confusion entirely and ensures nobody miscalculates during the biannual transition periods.
Travellers use time zone converters before departure to understand their flight arrival times in local time, calculate jet lag recovery windows, check when events at their destination correspond to home time (sports broadcasts, work deadlines, family calls), and figure out when to call home without waking people up. The converter is particularly useful for multi-leg itineraries crossing several time zones in a single journey.
Freelancers working with international clients navigate time zones constantly — for client calls, project deadline communication, and invoice timing. A freelancer in Karachi (PKT, UTC+5) working with a client in New York (EST, UTC−5) is 10 hours ahead, meaning a "9 AM Monday" client deadline is 7 PM Sunday Karachi time. Getting this right is the difference between hitting deadlines and missing them by a day.
Anyone hosting a webinar, live stream, online course session, podcast recording, or virtual event needs to communicate their start time to a global audience across multiple time zones. A YouTube live stream starting at 8 PM EST needs to be communicated as 1 AM GMT, 6:30 AM IST, and 9 PM CST for audiences in different regions to find it correctly. Time zone converters are a standard pre-launch checklist item for online event promotion.
Global financial markets open and close at specific local times that translate to very different hours in other time zones. The NYSE opens at 9:30 AM ET and closes at 4:00 PM ET. The London Stock Exchange opens at 8:00 AM GMT. The Tokyo Stock Exchange opens at 9:00 AM JST (12:00 AM GMT). Investors and traders in different time zones use converters to plan their active hours around market overlaps — the busiest, most liquid trading periods typically occur when two major markets are simultaneously open.
| City Pair | Typical Time Difference | Best Meeting Window (Source City) | Best Meeting Window (Target City) |
|---|---|---|---|
| New York ↔ London | 5 hrs (EST) / 4 hrs (EDT) | 9:00–11:00 AM EST/EDT | 2:00–4:00 PM GMT/BST |
| New York ↔ Paris/Berlin | 6 hrs (EST) / 5 hrs (EDT) | 9:00–11:00 AM EST/EDT | 3:00–5:00 PM CET/CEST |
| London ↔ Dubai | 4 hrs (GMT) / 3 hrs (BST) | 9:00 AM–1:00 PM GMT/BST | 12:00–4:00 PM GST |
| London ↔ Karachi | 5 hrs (GMT) / 4 hrs (BST) | 9:00 AM–12:00 PM GMT/BST | 2:00–5:00 PM PKT |
| London ↔ Mumbai | 5.5 hrs (GMT) / 4.5 hrs (BST) | 8:30 AM–11:30 AM GMT/BST | 2:00–5:00 PM IST |
| New York ↔ Dubai | 9 hrs (EST) / 8 hrs (EDT) | 8:00–11:00 AM EST/EDT | 5:00–8:00 PM GST |
| New York ↔ Mumbai | 10.5 hrs (EST) / 9.5 hrs (EDT) | 8:30–10:30 AM EST/EDT | 7:00–9:00 PM IST |
| London ↔ Sydney | 11 hrs (GMT) / 9 hrs (BST) | 8:00–9:00 AM GMT (winter only) | 7:00–8:00 PM AEDT |
| New York ↔ Tokyo | 14 hrs (EST) / 13 hrs (EDT) | Very limited overlap | Very limited overlap |
The most common time zone conversion error happens during the 1–3 week windows when the US and EU have transitioned to/from DST on different dates. During these periods, the US–Europe offset is temporarily different from its standard value. Always use a DST-aware converter for dates near late March, late October, and early November.
A meeting at 10 PM EST is 3 AM the next day in London. Many scheduling errors happen because people note the converted time but not the converted date. This calculator always shows the full date alongside the converted time precisely to prevent this.
The UK is not always at GMT. During British Summer Time (late March to late October), the UK is at UTC+1 (BST). A significant portion of the year, "UK time" means BST, not GMT. Always check which one applies for the date in question.
India (UTC+5:30) and Nepal (UTC+5:45) use non-standard offsets that are easy to misremember. When converting to or from these zones mentally, the 30-minute component is frequently lost. Always verify half-hour and quarter-hour offsets with a converter rather than relying on memory.
Just because 9 AM New York and 10 PM Tokyo is technically within both parties' days doesn't mean it's a comfortable meeting time. Always communicate with participants about their preferences rather than assuming any overlap window is acceptable — cultural work hour expectations vary significantly across regions.
A time zone is a region observing uniform standard time. Zones are defined as offsets from UTC, ranging from UTC−12 to UTC+14. The Earth's 24 primary zones are each nominally 15 degrees of longitude wide (one hour), but in practice boundaries follow political borders. The IANA tz database is the authoritative technical reference for all world time zones.
GMT (Greenwich Mean Time) is the time zone at 0° longitude, observed in the UK during winter. UTC (Coordinated Universal Time) is the international atomic clock standard. Both represent the same time value at the zero meridian, but UTC is the more precise scientific standard. For everyday conversion purposes they are interchangeable — the UK switches to BST (UTC+1) during summer, not UTC+1.
DST advances clocks by one hour in summer to extend evening daylight. Northern Hemisphere countries observe it roughly March–November; Southern Hemisphere countries September–April. Major non-observing countries include Japan, China, India, most of Africa, and several others. DST changes UTC offsets twice per year in observing regions, which is why DST-aware conversion tools are essential for accurate scheduling.
Find each zone's UTC offset, calculate the difference, and add or subtract from the source time. Example: 3 PM EST (UTC−5) to IST (UTC+5:30) — difference is +10:30. Add 10 hours 30 minutes to 3 PM: result is 1:30 AM the next day IST. Always verify DST applies for both locations on the specific date.
9–11 AM EST/EDT works well — it's 2–4 PM GMT/BST in the UK, within normal business hours for both. For US West Coast and UK, the overlap is tighter: 9 AM PST = 5 PM GMT, which is at the edge of UK business hours. Morning US time almost always works for UK; afternoon US time often falls outside UK hours.
Six, including territories: Eastern (UTC−5/−4), Central (UTC−6/−5), Mountain (UTC−7/−6), Pacific (UTC−8/−7), Alaska (UTC−9/−8), and Hawaii-Aleutian (UTC−10, no DST in Hawaii). Parts of Arizona observe Mountain Standard Time year-round without DST.
UTC+5:30 is Indian Standard Time (IST), used throughout India and Sri Lanka year-round without Daylight Saving Time. The unusual 30-minute offset reflects India's decision to use a single national time zone spanning its wide longitude range, splitting the difference between UTC+5 and UTC+6.
UTC is the universal standard for aviation, finance, military, internet protocols, and scientific work. When scheduling globally, specifying time in UTC alongside local times eliminates ambiguity, especially during DST transition periods. Major financial market hours: NYSE 9:30 AM–4:00 PM ET; LSE 8:00 AM–4:30 PM GMT; TSE 9:00 AM–3:30 PM JST.
The live world clock at the top of this page shows real-time current times for 8 major cities, updating every second. For any other city, select it from the "To" dropdown and the converter displays its current time immediately. Alternatively, search "[city] time" in Google for an instant answer.
Countries like India (UTC+5:30) and Nepal (UTC+5:45) use non-standard offsets to place their single national time zone at the geographic midpoint of their landmass rather than align with the nearest whole-hour zone. This is a political decision balancing geographic accuracy with the practicality of a single national time standard. Iran uses UTC+3:30, Australia's Lord Howe Island uses UTC+10:30/+11.