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Timezone Converter

convert times between any two time zones instantly

By Bikram NathLast updated

Paste any time and pick two IANA timezone names; the tool outputs the equivalent local time in each zone and highlights overlapping business hours between them. Useful for converting a UTC deploy timestamp like '2026-05-19 14:30 UTC' to '20:00 IST / 10:30 EDT' in one step. Unlike a world clock, it lets you find scheduling overlap windows across zones simultaneously.

In development

Interactive Timezone Converter — coming soon

We're still building the interactive Timezone Converter. The guide below explains exactly what it does and how to use it. In the meantime, here are DevLab tools that already work in your browser:

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What is Timezone Converter?

The tool takes a date and time, a source timezone, and one or more target timezones, then returns the equivalent local time in each. Drop in a CI log timestamp like '2026-05-19T08:45:00Z', add Asia/Kolkata and America/Chicago as targets, and get '14:15 IST / 03:45 CDT' without mental arithmetic.

Reach for this instead of timeanddate.com when you want to stay in a browser tab without navigating calendar UIs, or instead of worldtimeserver.com when the use case is a specific timestamp rather than 'what time is it now.' The overlap finder, which shows which hours two zones share during a working day, is the feature that separates it from single-conversion tools.

One practical gotcha: three-letter abbreviations like CST are ambiguous. CST is UTC-6 in North America and UTC+8 in China. The Intl.DateTimeFormat API that browsers use for timezone math operates on IANA names such as America/Chicago or Asia/Shanghai, not abbreviations, so always prefer the IANA form when entering zones manually to avoid getting the wrong hemisphere.

When to use Timezone Converter

✓Convert a UTC-stamped error log to your team's local times before writing a post-mortem or incident report.
→Schedule a cross-continent code review by checking the overlap window between IST, CET, and PST in one view.
⚡Verify a cron job's UTC schedule fires during business hours in the region it serves before merging the change.

Frequently Asked Questions

Does this handle India's UTC+5:30 and Nepal's UTC+5:45 offsets correctly?
Both IST (Asia/Kolkata, UTC+5:30) and NPT (Asia/Kathmandu, UTC+5:45) are defined in the IANA timezone database, so the conversion math handles them the same as any whole-hour offset. About a third of the world's named zones use half-hour or quarter-hour offsets. Australia/Lord_Howe is unusual even among fractional zones, shifting between UTC+10:30 in winter and UTC+11:00 in summer. As long as you select the IANA name rather than typing a raw offset manually, you get the correct result automatically.
Why does switching from 'EST' to 'America/New_York' give me a different offset in some months?
EST is a fixed offset, UTC-5, and never changes. America/New_York is a rule-based zone that observes Eastern Daylight Time at UTC-4 from mid-March to early November under the current U.S. schedule. If you book a meeting using EST in July, you are scheduling at a time no U.S. city actually observes in summer. Tools backed by Intl.DateTimeFormat use the IANA database, which applies the correct DST rule automatically when you select a named zone like America/New_York rather than a raw abbreviation.
How does the overlap finder calculate a shared working-hours window?
It assumes a standard 09:00 to 18:00 window in each selected zone, then finds the intersection: the hours when that window is simultaneously true for all chosen zones. Select London on BST (UTC+1) and San Francisco on PDT (UTC-7) and you get an 8-hour gap, leaving a 1-hour overlap at 17:00 to 18:00 BST and 09:00 to 10:00 PDT. There is no universal definition of working hours, so treat the 9-to-6 assumption as a starting point that you will likely need to adjust.
Does DST affect my conversion if I enter a future date several months out?
Yes. The IANA timezone database includes projected DST transition rules, so picking a date in late March for a European city causes Intl.DateTimeFormat to apply CEST (UTC+2) instead of CET (UTC+1) because that date falls past the spring transition. The caveat is that some countries announce rule changes with short notice. The U.S. and EU have both debated abolishing DST in recent years, meaning transitions more than 12 months out should be treated as provisional until the political decision is finalized and TZDB is updated.
Why might a timezone name I type return no result even though it appears in the IANA database?
Browser support for IANA zones depends on the copy of the timezone database bundled with the operating system, not the latest TZDB release directly. Chrome and Firefox typically lag one or two TZDB versions behind current. Newly created zones, renamed zones, or zones added after a country changes its DST rules may not appear until a browser or OS update ships. You can check availability in the browser console with Intl.supportedValuesOf('timeZone') and see whether the name you need is in the returned array before relying on it.

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