时区转换器
指导
时区转换器
Convert a date and time across multiple time zones simultaneously. Enter a source date, time, and time zone, then add as many target time zones as needed to see the converted times side by side. Supports 24-hour format toggle and all IANA time zones including DST-aware conversions.
如何使用
Set your source date and time, select the source time zone from the searchable dropdown, then use Search & Add Timezone to add destination time zones. All conversions update instantly. Toggle 24-hour format to suit your preference.
特征
- Multi-zone comparison – add unlimited destination time zones
- DST-aware – handles daylight saving time transitions correctly
- Full IANA timezone database – all standard time zones with city names
- Searchable zone selector – find zones by city, country, or UTC offset
- 24-hour toggle – switch between 12-hour and 24-hour display
- Real-time updates – conversions update as you change any input
常问问题
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What is the difference between UTC, GMT, and a time zone?
UTC (Coordinated Universal Time) is the primary time standard that clocks and time are regulated by, maintained by atomic clocks. GMT (Greenwich Mean Time) is a time zone at 0° longitude that is equivalent to UTC in winter but is a geographic time zone, not a time standard. A time zone is a region that observes a uniform standard time, defined by its UTC offset and DST rules. Most programming and systems use UTC as the baseline and convert to local time for display.
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How does daylight saving time affect time zone conversions?
DST shifts clocks forward (typically by 1 hour) during summer months to extend evening daylight. Not all regions observe DST, and those that do transition on different dates. When converting across DST boundaries, the UTC offset of a time zone changes — for example, Eastern Time is UTC−5 in winter (EST) and UTC−4 in summer (EDT). Always use IANA time zone IDs (e.g., America/New_York) rather than abbreviations (EST/EDT) for unambiguous DST-aware conversion.
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Why do time zone abbreviations cause confusion?
Many abbreviations are shared by multiple time zones: IST is India Standard Time (UTC+5:30), Israel Standard Time (UTC+2), and Irish Standard Time (UTC+1). CST is Central Standard Time (UTC−6), China Standard Time (UTC+8), and Cuba Standard Time (UTC−5). Using IANA identifiers (e.g., Asia/Kolkata, America/Chicago) eliminates ambiguity entirely. Abbreviations should only be used for display, never for parsing or calculation.
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What are the most common pitfalls in time zone handling for developers?
The most common pitfalls are: storing local times instead of UTC in databases, ignoring DST transitions when adding time intervals, using 3-letter abbreviations instead of IANA IDs, assuming all days have 24 hours (DST transitions create 23- and 25-hour days), and treating UTC offset as static (many zones change offset seasonally). Always store timestamps in UTC, convert to local time only at display time, and use a library with the IANA timezone database (Intl.DateTimeFormat, Moment-Timezone, date-fns-tz).
