# Time Zone Converter - Compare Cities Side by Side with Shared Working Hours

Page: https://hirantha.me/tools/time-zone-converter
Part of: Hirantha Sandaruwan Lakshan free tools (https://hirantha.me/tools)
Updated: 2026-10-15

Compare the time in up to six cities or any IANA time zone side by side, with UTC offsets, daylight saving, day changes, shared working hours and a share link.

This is a free tool that runs in the browser: open the page to use it. File tools process files on the visitor's own device; files are never uploaded or stored. No account, sign-up, payment or watermark.

Pick a date and time in one place and see what the clock reads in up to five more, with the UTC offset, whether the place is on summer time, and whether the date changes. A bar shows each place's working hours across the day and outlines the hours they all share. Choose from about 65 popular cities or search every time zone your browser knows. The page handles the days the clocks change, and a link keeps your choices. Everything runs in your browser.

You enter a date and time for one place. The page works out the exact UTC moment, then asks your browser what the clock reads in each other place, using Intl.DateTimeFormat, which draws on the IANA time zone database. No time zone data is bundled with the page and no network call is made. The popular list has about 65 cities, and the search also covers every zone returned by Intl.supportedValuesOf("timeZone") when your browser has it (MDN, checked 2026-10-15). Frankfurt and Berlin share the zone Europe/Berlin, and Doha uses Asia/Qatar.

Places that change their clocks make some local times missing or doubled. US clocks go forward on the second Sunday of March at 02:00 and back on the first Sunday of November at 02:00 (NIST, checked 2026-10-15). UK and EU clocks go forward on the last Sunday of March and back on the last Sunday of October, at 01:00 UTC in the EU (GOV.UK and Directive 2000/84/EC, checked 2026-10-15). A time that clocks skip, such as 02:30 on 8 March 2026 in New York, is moved forward by the length of the jump and read as 03:30. A time that happens twice, such as 01:30 on 1 November 2026 in New York, uses the first occurrence, which is still on summer time. The page tells you when it has done this. These are the same choices as the compatible mode of JavaScript's Temporal (the same as Date) and Python's zoneinfo with fold=0.

Because Europe and North America change on different dates, gaps between cities move during the year. New York is 5 hours behind London most of the time, but only 4 hours behind from 8 March 2026, when the US moves, until the UK moves on 29 March. The bar covers the day of the place you entered the time in, which is 23 or 25 hours long on a day its clocks change. Working hours are 09:00 to 17:00 by default and you can change them. The page does not know about weekends or public holidays, and some places do not work Monday to Friday.

Your browser's time zone data has a version, and browsers differ. Rules changed recently in several places: the IANA release notes list Paraguay (release 2025a), Chile's Aysen Region (2025b), Moldova (2026a), British Columbia (2026b), Alberta and Morocco (2026c), Inuvik (2026d) and Manitoba (2026e), and the latest release at 2026-10-15 was 2026e. A browser with older data can show a wrong offset there. Vancouver and the other affected cities are therefore not in the popular list, as on the Colombo time converter, and a warning appears if you pick one from the full list. Confirm an important meeting time with the other side.

The link stores the places, the time and the place the time was entered in after the # sign, for example #z=colombo,london&b=colombo&t=2026-10-15T14:30. Browsers do not send that part to a server (RFC 3986, checked 2026-10-15). When a link is opened, every item is checked: it must be short, the places must be known city ids or time zone names your browser accepts (at most six), and the time must be a real date and time. Anything else is ignored.

When the clocks change in popular places (dates checked against Python zoneinfo, tzdata 2026c, on 2026-10-15):
| Place | Standard time | Summer time | Summer time starts, 2026 and 2027 | Summer time ends, 2026 and 2027 |
| --- | --- | --- | --- | --- |
| New York, Toronto | UTC-5 | UTC-4 | 8 Mar 2026, 14 Mar 2027 | 1 Nov 2026, 7 Nov 2027 |
| Chicago | UTC-6 | UTC-5 | 8 Mar 2026, 14 Mar 2027 | 1 Nov 2026, 7 Nov 2027 |
| Los Angeles | UTC-8 | UTC-7 | 8 Mar 2026, 14 Mar 2027 | 1 Nov 2026, 7 Nov 2027 |
| London | UTC+0 | UTC+1 | 29 Mar 2026, 28 Mar 2027 | 25 Oct 2026, 31 Oct 2027 |
| Berlin, Paris | UTC+1 | UTC+2 | 29 Mar 2026, 28 Mar 2027 | 25 Oct 2026, 31 Oct 2027 |
| Sydney | UTC+10 | UTC+11 | 4 Oct 2026, 3 Oct 2027 | 5 Apr 2026, 4 Apr 2027 |
| Auckland | UTC+12 | UTC+13 | 27 Sep 2026, 26 Sep 2027 | 5 Apr 2026, 4 Apr 2027 |
| Colombo | UTC+5:30 | none | none | none |
| Dubai | UTC+4 | none | none | none |
| Singapore | UTC+8 | none | none | none |
| Tokyo | UTC+9 | none | none | none |

Q: How do I convert a time from one time zone to another?
A: Pick the place the time is in, enter the date and time, and add the other places. The page converts to UTC and back, so each row shows the local time, date and UTC offset. The difference is the gap between the two offsets, which can change during the year if either place uses summer time.

Q: What time zone is Sri Lanka in?
A: Sri Lanka Standard Time, UTC+5:30, with no daylight saving. The IANA name is Asia/Colombo. The Colombo time converter on this site has more detail on how Sri Lanka's offset has changed over the years.

Q: Why does the time difference between two cities change during the year?
A: Because each place changes its clocks on its own dates, or not at all. The US moves on the second Sunday of March and the first Sunday of November, the UK and EU on the last Sundays of March and October, so the gap between New York and London is 4 hours for a few weeks twice a year instead of 5.

Q: What happens to a time that does not exist when clocks change?
A: It is moved forward by the length of the jump, so 02:30 in New York on 8 March 2026 is read as 03:30. A time that happens twice uses its first occurrence. The page shows a note whenever it does this.

Q: Why might another site show a different time for the same city?
A: Sites use different versions of the time zone database. Rules for some places changed recently, for example British Columbia, Alberta and Manitoba in Canada and Morocco, and a browser or site with older data shows the old offset. Check an important time with the people involved.

Q: What does the share link contain, and is it private?
A: The places, the time and the place the time was entered in, written after the # sign. Browsers do not send that part to a server. When you open a link, the page checks every item and ignores anything that is not a known place or a real time.

Q: How many places can I compare, and does it know about weekends?
A: Up to six. The working hours bar uses the same start and end hours everywhere and does not know about weekends or public holidays, which differ between countries.

Sources: IANA Time Zone Database, project page (latest release 2026e at 2026-10-15) (https://www.iana.org/time-zones); IANA tz database release notes (NEWS): changes in 2025 and 2026, checked 2026-10-15 (https://raw.githubusercontent.com/eggert/tz/main/NEWS); Daylight Saving Time - NIST (US rule and 2026 dates), checked 2026-10-15 (https://www.nist.gov/pml/time-and-frequency-division/popular-links/daylight-saving-time-dst); When do the clocks change - GOV.UK (UK dates for 2026 and 2027), checked 2026-10-15 (https://www.gov.uk/when-do-the-clocks-change); Directive 2000/84/EC on summer-time arrangements - EUR-Lex (last Sunday of March and of October, 01:00 GMT), checked 2026-10-15 (https://eur-lex.europa.eu/eli/dir/2000/84/oj); Seasonal changes of time - European Parliament summary of Directive 2000/84/EC, checked 2026-10-15 (https://oeil.europarl.europa.eu/oeil/en/document-summary?id=1551605); Intl.supportedValuesOf() - MDN, checked 2026-10-15 (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/supportedValuesOf); Temporal.ZonedDateTime, ambiguity and gaps (the compatible option) - MDN, checked 2026-10-15 (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal/ZonedDateTime); RFC 3986 section 3.5, Fragment - the fragment is handled by the user agent, checked 2026-10-15 (https://www.rfc-editor.org/rfc/rfc3986#section-3.5)

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