Unix Timestamp Converter

A Unix timestamp represents time elapsed since the Unix epoch at1970-01-01T00:00:00Z. It gives software a compact numeric way to represent an absolute instant independently of a human-readable calendar format.

Traditional Unix time counts seconds, while JavaScript and many modern systems commonly work with milliseconds.

Seconds count one unit per second after the epoch. Milliseconds count one thousand units per second. A contemporary seconds value is often around 10 digits and a milliseconds value around 13 digits, but digit count is only a common pattern, not the definition.

This converter always uses the unit selected in the interface and never relies on digit count alone.

Epoch time is a numeric time representation measured from a defined reference instant. In everyday development, “epoch time” often means Unix time measured from the Unix epoch, although other systems can define different epochs.

1. Enter the Unix timestamp.
2. Select whether the value is in seconds or milliseconds.
3. Select Convert to Date.
4. Review UTC, browser local time, ISO 8601, seconds, and milliseconds.

1. Choose a date and time in the local date-time field.
2. Remember that datetime-local contains no timezone information.
3. Select Convert to Timestamp.
4. Copy the seconds, milliseconds, or ISO 8601 result as needed.

A Unix timestamp identifies an absolute instant and does not carry a timezone. UTC and local time are different formatted representations of that same instant. Local Time on this page uses the timezone configured by your browser or device.

0 seconds converts to 1970-01-01T00:00:00.000Z.

A fixed modern example, 1700000000 seconds, converts to2023-11-14T22:13:20.000Z.

Negative Unix values represent dates before the epoch. For example, -1 second converts to 1969-12-31T23:59:59.000Z. This converter accepts finite negative values.

A signed 32-bit Unix seconds field reaches its maximum value in January 2038. Systems that still use that representation can overflow. JavaScript Date uses a different numeric date model and is not limited to signed 32-bit Unix seconds, although it still has a finite range.

JWT exp, iat, and nbf claims commonly use NumericDate values expressed as Unix seconds. Use the JWT Decoderto inspect those claims before converting a value here.

• Translate API or database epoch values into readable UTC and local times.
• Compare seconds and milliseconds when an integration shows an unexpected date.
• Create Unix values for tests, scheduled events, logs, or expiration fields.
• Inspect JWT NumericDate claims alongside their original integer values.