Unix Timestamp Converter

A Unix timestamp counts the time elapsed since 00:00:00 UTC on 1 January 1970 — the Unix epoch. Because it is a single number in UTC, it sidesteps time zones, daylight saving and date formatting entirely, which is why nearly every system stores time this way and formats it only at the last moment.

This is the single most common timestamp bug. Unix timestamps are traditionally in seconds, and that is what databases, JWT claims, Go, Python and date +%s produce. JavaScript's Date.now() returns milliseconds, as do Java and most JavaScript APIs.

Get it wrong in one direction and your date lands in January 1970. Get it wrong in the other and you end up in the year 57,655. Both are unmistakable once you know to look for them.

This tool guesses the unit from the magnitude — a ten-digit number is seconds, a thirteen-digit one is milliseconds — and tells you which it chose. The unit selector always overrides the guess, so you are never at the mercy of a heuristic.

1. Paste a timestamp into the left panel to see it as a date in UTC, your local zone, ISO 8601 and more.
2. Pick a date in the right panel to get the timestamp for it.
3. Use the live current time at the top when you need “now” in either unit.

• Reading the exp or iat claim from a JWT.
• Making sense of a timestamp column in a database or log line.
• Setting an expiry time for a cache entry or a signed URL.
• Checking whether a scheduled job ran when you expected.
• Comparing timestamps recorded by systems in different zones.

• Local time comes from your device. If your clock or time zone is wrong, so is the local column — UTC and ISO are unaffected.
• Unix time ignores leap seconds. A timestamp is not quite the true number of SI seconds since the epoch, and for almost all purposes that is fine.
• 32-bit systems storing seconds in a signed integer overflow on 19 January 2038. This tool uses 64-bit floating point and is not affected, but the systems you query might be.
• Dates before 1970 are negative timestamps. They are handled correctly here, though some systems reject them.
• The date picker works in your local zone. To enter a UTC time, use the timestamp field directly.