Time Format Converter — Unix Timestamp / ISO 8601 / RFC 2822 / Localized Display

Input (supports multiple formats)

Enter time or timestamp

Supported Format Examples：
• Unix Seconds: 1633046400
• Unix Milliseconds: 1633046400000
• ISO 8601: 2025-10-20T15:00:00Z
• Local Timezone: 2025-10-20 15:00:00
• RFC 2822: Mon, 20 Oct 2025 15:00:00 +0800

Enter Timezone (Optional)

Output Result

Quick Example

Input：1633046400
Output Example：
 - Unix (Seconds): 1633046400
 - Unix (Milliseconds): 1633046400000
 - ISO: 2021-10-01T00:00:00Z
 - Localized Display: 2021-10-01 08:00:00 (UTC+8)

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Frequently Asked Questions (FAQ)

A Unix timestamp represents the time since 1970-01-01 00:00:00 UTC.
- **Seconds-based timestamp** (10 digits, e.g. 1633046400) is common in databases and APIs.
- **Milliseconds-based timestamp** (13 digits, e.g. 1633046400000) is common in JavaScript (Date.now()).
This tool auto-detects length to distinguish seconds/milliseconds.

UTC (Coordinated Universal Time) is the global time standard that replaced GMT.
- UTC is not a timezone; it is the zero offset (+00:00).
- Local time worldwide is expressed as UTC+offset, e.g. China is UTC+8.
- All conversions in this tool are based on UTC.

- ISO 8601: Defined by ISO, structured and includes timezone, widely used in APIs, e.g. 2025-10-20T15:00:00+08:00.
- RFC 2822: Defined by IETF, natural format for emails/HTTP, e.g. Mon, 20 Oct 2025 15:00:00 +0800.
- RFC 3339: A subset of ISO 8601, widely used in JSON APIs.
Modern systems prefer ISO 8601 / RFC 3339.

This is caused by timezone differences and Daylight Saving Time (DST).
- UTC is the universal base.
- Local time = UTC + offset (which may change with DST).
Example: 2025-10-20 15:00:00 UTC shows as 23:00:00 (UTC+8) in Shanghai, and 11:00:00 (UTC-4) in New York.

- Julian Date (JD): Used in astronomy, starts from Jan 1, 4713 BC at noon. 1 day = 1 unit, integer part = days, fractional part = time of day.
- Modified Julian Date (MJD): Simplified, defined as MJD = JD - 2400000.5, starting from 1858-11-17.
Commonly used in observatories, aerospace, and GPS systems.

GPS Time started on 1980-01-06, and does not account for leap seconds.
- GPS vs UTC = leap second difference, currently about +18s.
- GPS signals provide Week Number and Seconds of Week.
In precise navigation and satellite communications, UTC vs GPS differences must be considered.

- Unix Timestamp: Integer, easy to compute.
- ISO 8601 / RFC 3339: Standardized text, common in APIs.
- RFC 2822: Used in emails/HTTP.
- Localized Date Formats: YYYY/MM/DD HH:mm:ss, varies by region.
- Julian Date / MJD: Astronomy, aerospace.
- GPS Time: Satellite navigation.
- POSIX Time: Used in Unix-like systems, same as Unix timestamp.

- In software development, logs and databases need precise, unified formats.
- In science and engineering, Julian Date and GPS time are key standards.
- Global apps must handle timezone and DST correctly.
This page provides an all-in-one tool to quickly convert between formats, avoiding manual errors.