Unix Timestamp Converter - CodeToolbox.pro

Convert between Unix timestamps and human-readable dates in both directions. All conversion happens locally in your browser — nothing is uploaded.

What is a Unix Timestamp?

A Unix timestamp counts the number of seconds since January 1, 1970 00:00:00 UTC (the "Unix epoch"), not counting leap seconds. Most systems store timestamps as 32-bit or 64-bit integers: 10 digits for seconds, 13 digits for milliseconds. JavaScript's Date.now(), Python's time.time(), and MySQL's UNIX_TIMESTAMP() all produce variants of this value.

Common Use Cases

Debugging logs: Server logs often print raw timestamps — convert them to read what time an error actually occurred.
API responses: Many JSON APIs return "created_at": 1728000000 instead of an ISO date.
Database queries: Filter by date ranges using UNIX_TIMESTAMP() in MySQL or EXTRACT(EPOCH FROM ...) in PostgreSQL.
JWT & token expiry: JWT claims carry exp and iat as Unix seconds — verify them before debugging auth issues.
Signed URLs: Cloud storage presigned URLs embed an expiry timestamp; convert it to know when access lapses.

💡 Pro Tip: Seconds vs. Milliseconds

The classic bug: JavaScript and Java use milliseconds (13 digits, e.g. 1728000000000), while Go, PHP, Python, and most databases use seconds (10 digits, e.g. 1728000000). A 13-digit value passed to a seconds-only API is off by a factor of 1000 — usually landing in 1973 or the year 5138. When in doubt, this tool's Auto-detect mode tells you which unit a value looks like.

Frequently Asked Questions

Why does my timestamp convert to 1970 or 5138?

You're mixing units. A seconds-value read as milliseconds (multiplied by 1000) lands near 1970; a milliseconds-value read as seconds lands in the year 5138. Check the digit count: 10 digits = seconds, 13 digits = milliseconds. Auto-detect handles this automatically.

Is a Unix timestamp timezone-dependent?

No. A Unix timestamp is an absolute point in time — the same integer represents the same instant everywhere on Earth. Only the displayed date changes with your timezone. This converter shows your local time and UTC side by side so you can see both.

How do I get the current timestamp in code?

JavaScript: Math.floor(Date.now() / 1000) for seconds (or Date.now() for ms). Python: int(time.time()). Go: time.Now().Unix(). PHP: time(). MySQL: SELECT UNIX_TIMESTAMP();. PostgreSQL: SELECT EXTRACT(EPOCH FROM now());. Bash: date +%s.

What about dates before 1970?

They're valid too — negative timestamps. The Unix epoch is just a reference point; -86400 is exactly one day before the epoch (1969-12-31 UTC). 32-bit signed integers cover 1901–2038, which is why the Year 2038 problem affects old systems: they'll overflow at 03:14:07 UTC on January 19, 2038.

Is ISO 8601 better than a Unix timestamp?

For storing in JSON, ISO 8601 strings (e.g. 2026-10-04T12:30:00Z) are human-readable and unambiguous about timezone — but parsing them costs CPU and string handling. Unix timestamps are compact, trivially sortable, and timezone-free. Many teams store UTC ISO strings in databases and convert to Unix seconds only at API boundaries. Either works if you pick one consistently.