Time Zone Converter

How do you convert a local time across cities?

Enter the source city's date and time, then add the destinations. The first row defines what your input means: 09:00 in New York is interpreted as a New York wall-clock time, not as your computer's local time. Each destination shows that same instant with its own local date, UTC offset, and DST badge. Results update as you change the inputs; there is no separate conversion button.

For a worked example, put America/New_York first and choose January 15 at 09:00. With the browser's current winter rules for these zones, New York is UTC−5, so the instant is 14:00 UTC. Add Europe/London, Asia/Kolkata, Asia/Kathmandu, and Asia/Tokyo to reproduce the following comparison. The calculation is destination local time = UTC instant + destination offset, carrying into another date when necessary.

One January instant shown in five cities, using the 24-hour display

City	UTC offset	Local time	Local date
New York	UTC−5	09:00	January 15
London	UTC+0	14:00	January 15
Kolkata	UTC+5:30	19:30	January 15
Kathmandu	UTC+5:45	19:45	January 15
Tokyo	UTC+9	23:00	January 15

Changing New York to 10:00 moves Tokyo to 00:00 on January 16. Read the date below each result before sending a deadline or invitation. Half-hour and quarter-hour offsets remain intact in the main results; they are not rounded to whole hours.

How does the converter handle dates and daylight saving time?

The converter resolves your source wall time to a UTC instant, then formats that instant through the browser's Intl.DateTimeFormat API for every selected IANA zone. It uses the browser's time zone data rather than looking up a live conversion service. A time difference is therefore specific to the chosen date. Do not reuse a January difference for a summer appointment without checking again.

Every row shows the computed UTC offset. The DST on or DST off badge is a simpler indicator: the code compares offsets on January 1 and July 1 and marks the larger offset as daylight saving when they differ. This is a heuristic, not a complete classification of unusual seasonal or political changes. Use the actual date-specific offset when interpreting a result. An additional note looks for the next offset change over the following 366 days.

A forward clock change can make a local time nonexistent. The tool rejects that input and, when available, offers a later time through a Use button instead of silently adjusting it. A backward change can make the same local time occur twice. The converter chooses the earlier occurrence and has no control for selecting the later one. Invalid calendar dates are rejected too. For an appointment in a repeated hour, confirm which occurrence the participants intend.

How do you find a meeting time within everyone's working hours?

Expand Working hours for each city and edit Work starts, Work ends, and Working weekdays. The default schedule is Monday through Friday, 09:00–17:00, but each zone has its own settings. This lets a part-time colleague finish earlier or a team use a different weekend. Schedules belong to zones, so they do not represent multiple people with different availability in the same city.

Shared working hours checks each minute between the start and end of the reference city's selected calendar day. It uses every city's local date and weekday at that instant. With New York and London on a January weekday and both set to 09:00–17:00, the common window is 09:00–12:00 in New York, corresponding to 14:00–17:00 in London. Adding a distant zone can eliminate that window without making the time conversion itself invalid.

Best meeting slots · 30 minutes lists up to five earliest nonoverlapping half-hour slots inside the shared windows. It does not rank fairness, rotate inconvenient hours, or inspect anyone's calendar. A twenty-minute overlap is still displayed as a shared window but cannot produce a thirty-minute suggestion. When no overlap exists, adjust schedules deliberately or choose another reference date rather than assuming the converter found a scheduling error.

What do overnight shifts and the colored grid mean?

A work end earlier than the start means an overnight shift. For example, a Monday 22:00–06:00 schedule includes Tuesday before 06:00 as part of Monday's shift. Equal start and end times mean no working hours, rather than a full working day. Unchecking every weekday also leaves no working time. These settings affect shared windows as well as the row's grid colors.

Each row has 24 samples, one elapsed hour apart from reference midnight. Green means working hours; yellow means outside work during local hours from 07:00 up to 22:00; dark means the remaining nonworking night hours. The visible cells show hour numbers only. Their accessible labels include minutes, which matter for fractional offsets. Use the main time result and shared-window labels for precise minutes.

The grid is an overview rather than a minute-by-minute day planner. It always has 24 cells, even when a reference day contains a clock change. The shared-window calculation instead follows the actual boundaries of that local calendar day. Around a transition, use those windows and the displayed UTC offsets to understand availability rather than counting colored cells.

Why use city names and what happens when you reorder them?

Abbreviations such as IST and CST are ambiguous across regions. IANA identifiers such as Asia/Kolkata and America/Chicago specify which region's clock rules to apply. Every row prints its identifier. UTC provides a fixed reference; Europe/London represents London's seasonal rules. Choosing a location is more precise than assuming a familiar abbreviation always has one offset.

Search accepts listed city names, IANA identifiers, and selected aliases such as Mumbai, NYC, and Munich. Accent normalization lets local names match without accents. This is a curated alias list, not a search for every town or a location lookup. If your town does not appear, choose an appropriate listed zone after confirming it follows the same rules.

Use Up, Down, or dragging to reorder rows. Moving another city into first place preserves the text in Date and Time but reinterprets it in the new reference zone. It therefore changes the instant, rather than merely rearranging an unchanged conversion. Recheck the inputs afterward. Use 12-hour clock and Use 24-hour clock change display style without changing the selected instant.

How do sharing, calendar downloads, and local saving differ?

Copy summary produces one line with the reference date and each city's clock time. Because destinations can fall on another day, check their row dates before relying on that compact summary. Copy link preserves the date, time, ordered zones, clock style, and individual schedules in the URL fragment after #. A recipient can reopen the setup, and anyone with that full link can read those settings.

Add to calendar downloads meeting.ics, containing a one-hour event titled Meeting at the entered time with the conversion summary as its description. It does not automatically choose a suggested slot. Suggestions are thirty minutes long, so enter a proposed start yourself and review the exported event's duration in your calendar application. Downloading the file does not send invitations or check participants' availability.

The browser locally remembers the zone list, and Clear empties it. Ordinary local saving does not preserve the meeting date, input time, schedules, or clock style; use a copied link to restore those together. Conversion itself happens locally. Its rules depend on the browser's installed time zone data, so recently changed regional rules may require an updated browser or operating system.

Can you convert timestamps or count days instead?

Use the Unix Timestamp Converter when your starting value is an epoch number from a log or API response rather than a local date and clock time. For the calendar interval between two appointments, open the Date Difference Calculator. This page compares one instant across zones and searches working schedules for one reference date; it does not create a recurring meeting series.