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.

1. Enter a calendar date such as 1970-01-01, or a date-time with Z or a numeric UTC offset.
2. Select Convert ISO 8601, or press Enter.
3. Review the normalized UTC value, browser-local display, Unix seconds, and Unix milliseconds.
4. Copy the representation required by your application or API.

For example, 2023-11-15T06:13:20+08:00 and2023-11-14T22:13:20Z represent the same instant.

ISO 8601 defines a broad family of representations. This converter deliberately supports calendar dates in YYYY-MM-DD form and the common Internet date-time profileYYYY-MM-DDTHH:mm:ssZ, including fractional seconds and numeric offsets such as+08:00 or -05:00.

A date-only value is interpreted as midnight UTC. A date-time without a timezone is rejected because it does not identify an unambiguous instant; use the Local Date & Time field when the browser timezone should be used. Week dates, ordinal dates, durations, intervals, and leap seconds are not supported.

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.

Current Unix seconds commonly have about 10 digits and current Unix milliseconds about 13, but digit count is only a heuristic. Historical dates, far-future dates, decimals, and application-specific values can break that assumption.

The input displays a non-authoritative hint while the selected unit remains decisive. If a conversion lands thousands of years away from the expected date, check the unit first.

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.
• Normalize ISO 8601 values with different offsets to one UTC representation.
• Create Unix values for tests, scheduled events, logs, or expiration fields.
• Inspect JWT NumericDate claims alongside their original integer values.