Convert Unix timestamps to human-readable dates and back again. Handle seconds, milliseconds, and timezones correctly with a free online converter.

Open any API response, server log, or database export and you will eventually meet a number like 1699999999 where a date should be. That number is a Unix timestamp: the count of seconds since midnight on January 1, 1970, in UTC. Computers love it because it is compact, unambiguous, and easy to compare. Humans hate it because nobody can read it. A Timestamp Converter translates in both directions, turning raw epoch numbers into readable dates and readable dates back into epoch numbers.

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h2>Where timestamps show up

• API responses: fields like created_at and expires_at are routinely epoch integers.
• Databases: many systems store event times as integers for fast sorting and indexing.
• Logs: server and application logs stamp entries with epoch time for precision.
• Tokens and sessions: expiry times in authentication payloads are almost always timestamps.

If you debug any of these, you will convert timestamps weekly, which makes a fast converter worth bookmarking.

Converting in either direction

1. Open the converter and paste the timestamp, for example 1699999999.
2. Read the human date it corresponds to, in UTC and your local timezone.
3. To go the other way, enter a date and time to get the matching epoch number.
4. Double-check whether your source uses seconds or milliseconds before trusting the result.

Seconds versus milliseconds: the classic trap

JavaScript's Date.now() and many modern APIs count in milliseconds, producing thirteen-digit numbers like 1699999999000, while classic Unix time uses ten-digit seconds. Paste a millisecond value into a seconds-based converter and you will land somewhere in the year 56,000. If your converted date looks absurd, divide or multiply by one thousand and try again. This single mistake accounts for most timestamp confusion.

Timezone honesty

Epoch time itself has no timezone: it is always seconds since the UTC epoch. Timezones only enter when a human reads it. A converter should show you both the UTC instant and the local interpretation, and you should always confirm which one your system expects. Daylight saving transitions make this doubly important: the same local clock time can occur twice or never on switchover days, while the timestamp underneath stays unambiguous. When in doubt, store and compare in UTC, and convert to local time only for display.

Frequently asked questions

What is the maximum Unix timestamp?

On 32-bit systems, signed timestamps overflow in January 2038. Modern 64-bit systems handle far larger values, so this mostly matters for legacy embedded software.

Why do some timestamps have decimals?

Fractional timestamps add sub-second precision, common in high-frequency logging and scientific data. Most converters accept them fine.

Can I convert a date before 1970?

Yes. Dates before the epoch are simply negative numbers. Support varies by tool, so test with a known date first.

How do timestamps relate to ISO 8601 dates?

They describe the same instant in different clothing. ISO 8601 like 2023-11-15T08:30:00Z is human-readable; the timestamp is machine-friendly. Convert between them freely.

Final thought

Timestamps are the lingua franca of machine time, and fluency pays off every time you touch an API or a log file. Keep the converter handy, watch out for the milliseconds trap, and think in UTC. When those API responses arrive wrapped in JSON, a JSON Viewer and a JSON Validator complete the toolkit.