Time Zone Converter
Convert time between any cities or IANA time zones instantly. Compare local wall-clock times, check daylight saving shifts, and track date differences across midnight.
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Time Zone Converter FAQs
Clear answers about time zones, daylight saving switches, UTC offsets, and midnight boundaries.
How do daylight saving time (DST) changes affect time zone conversions?
When a region enters Daylight Saving Time, its local clocks shift forward by 1 hour (for example, from UTC-5 EST to UTC-4 EDT in the eastern United States, or from UTC+0 GMT to UTC+1 BST in the UK). This changes the time difference between cities. Our converter uses the official IANA Time Zone Database for the specific date you select, correctly calculating whether DST is active.
Why is the difference between Delhi and New York sometimes 9.5 hours and other times 10.5 hours?
India operates on Indian Standard Time (IST, UTC+05:30) year-round without daylight saving changes. New York switches between Eastern Daylight Time (EDT, UTC-04:00) during summer and Eastern Standard Time (EST, UTC-05:00) during winter. Therefore, Delhi is 9 hours and 30 minutes ahead of New York in summer/fall, and 10 hours and 30 minutes ahead in winter.
How does the converter handle crossing midnight and the date change?
When converting time across large longitudinal spans, the resulting local time frequently crosses midnight into either the next calendar day or the previous day. The converter computes both the exact local wall-clock time and the calendar date, displaying a clear "Previous day" or "Next day" badge so you never miss a cross-day meeting or flight schedule.
What is an IANA time zone identifier and why is it preferred over abbreviations?
Three-letter abbreviations like CST are ambiguous because they can represent Central Standard Time (US, UTC-6), China Standard Time (UTC+8), or Cuba Standard Time (UTC-5). IANA identifiers (such as America/New_York or Asia/Kolkata) uniquely specify a geographic location along with its full historical and future daylight saving transition rules.
Does this converter make requests to external time APIs?
No. The converter runs 100% client-side in your browser using native JavaScript Intl.DateTimeFormat APIs. It requires zero network requests, works offline, preserves complete privacy, and provides instantaneous results.