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Timestamp Converter

Unix timestamps, ISO 8601, human dates. Paste one, see them all.

Input
Results
Detected as
seconds
Unix (seconds)
1711545600
Unix (milliseconds)
1711545600000
ISO 8601
2024-03-27T13:20:00.000Z
UTC
Wed, 27 Mar 2024 13:20:00 GMT
Local
March 27, 2024 at 10:20:00 PM
Day of week
Wednesday
Relative
2 years ago
Your timezone
Asia/Seoul

What this does

DEVS: Auto-detects seconds vs milliseconds (threshold: 1e12). Date.toISOString() for ISO, Intl.DateTimeFormat for timezone detection. "Now" button calls Date.now().

Paste a Unix timestamp, an ISO 8601 string, or a plain date and see every common format at once. Seconds, milliseconds, ISO, UTC, local time, day of the week, relative time, and your detected timezone. The "Now" button grabs the current moment.

Common use cases

Debugging API responses. You're staring at 1711545600 in a JSON payload and wondering what day that is. Paste it, see "Wednesday, March 27, 2024." Done.

Converting between formats for logs, database queries, or configuration files that each want timestamps in their own special format. Postgres wants ISO. Your cron docs use Unix. The PM asks for a human date. One paste, all three answers.

Checking token expiration. JWT exp claims are Unix timestamps in seconds. Paste the value, see if it's in the past. The relative time field tells you exactly how long ago it expired.

Things to know

The seconds-vs-milliseconds detection uses a simple threshold: if the number is larger than one trillion, it's treated as milliseconds. Smaller numbers are seconds. This works because one trillion milliseconds is roughly 2001, and almost nobody is converting timestamps from before then. If you do need pre-2001 millisecond precision, divide by 1000 first.

Date string parsing uses your browser's built-in Date constructor, which handles ISO 8601, RFC 2822, and most readable formats like "March 27, 2024" or "2024/03/27". It's forgiving but not magic. Ambiguous formats like "03/04/2024" will follow your browser's locale (month-first in the US, day-first elsewhere).

The timezone shown is yours, detected via Intl.DateTimeFormat. The UTC and local rows let you compare the same moment in both. Handy when you're coordinating across time zones and need to know "what time is that in UTC?"

Privacy

Everything runs in your browser. The timestamps you paste don't leave your machine. We don't even know you're here, technically.

Questions

What is a Unix timestamp, or epoch time?

It's the number of seconds since January 1, 1970, UTC, also called the Unix epoch. 1711545600 is a Unix timestamp. Counting from one fixed moment makes time easy for computers to store and compare, and unreadable for the rest of us. That's what this tool is for.

Is my timestamp in seconds or milliseconds?

Seconds are 10 digits right now, milliseconds are 13. This tool auto-detects: anything over a trillion is treated as milliseconds, everything else as seconds. If you're working with pre-2001 millisecond values, divide by 1000 first.

How do I convert an epoch timestamp to a date?

Paste the number and read the ISO, UTC, and local rows. 1711545600 comes back as Wednesday, March 27, 2024. The relative-time row tells you how long ago, or ahead, that is.

What's the Year 2038 problem?

Systems that store Unix time in a signed 32-bit integer run out of room on January 19, 2038, and roll over into negative numbers. Most modern systems use 64-bit time and are fine. It's the new Y2K, with more lead time.