Unix Timestamp Converter

Convert between Unix timestamp and human-readable date. Supports seconds, milliseconds, and ISO 8601 format. Everything runs in your browser.

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FAQ

API Debugging Log Analysis Backend Integration Time Conversion
Is the timestamp in seconds or milliseconds?
Most modern systems (JavaScript, Java) use milliseconds (13 digits). Older systems (PHP, Python) use seconds (10 digits). Divide by 1000 to convert milliseconds to seconds.
What's the difference between Beijing time and UTC?
UTC is the world standard. Beijing Time is UTC+8. Databases store UTC; frontends display local time—the conversion happens in between.
What's special about 2026 and 2038?
32-bit systems store time as a signed integer. On January 19, 2038, it overflows. Modern systems use 64-bit and are not affected.
How do I convert Beijing time to a timestamp?
Enter Beijing time and the tool outputs Unix timestamp (seconds or milliseconds, your choice), ready to copy for API calls.
Does the result show the day of the week?
Yes—full date, day of week, and timezone are all displayed. No more manual calculation needed.
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Why Timestamp Conversion Matters

Unix timestamps are used because they are unambiguous numbers. APIs, databases, logs, message queues, and backend services can compare two timestamps without worrying about language, date formatting, or daylight saving display rules. Humans, however, need readable dates. A timestamp converter bridges that gap when debugging event logs, token expiry, scheduled jobs, webhook payloads, and database records.

The most common mistake is confusing seconds and milliseconds. Unix time in seconds usually has 10 digits, while JavaScript timestamps in milliseconds usually have 13 digits. If a date appears thousands of years in the future or before 1970, the value was probably interpreted with the wrong unit.

Common Timestamp Mistakes

Seconds vs milliseconds
1748396400 is seconds. 1748396400000 is milliseconds. Multiply seconds by 1000 for JavaScript Date, or divide milliseconds by 1000 for many backend APIs.
Local time vs UTC
A timestamp represents one exact moment. The displayed clock time changes by timezone, but the underlying moment does not. Store UTC; display local time at the edge of the app.
Expired tokens and scheduled jobs
JWT exp, cron logs, and webhook retries often use timestamps. Converting them helps you see whether an issue is caused by real expiry, clock drift, or a timezone assumption.

Example: API Debugging

Unix seconds:      1748396400
Unix milliseconds: 1748396400000
ISO 8601 UTC:      2025-05-28T03:00:00.000Z