Unix Timestamp Converter

How to use this tool

1. Enter the source in the input field.
2. Choose the direction and numeric unit, then select all results, an ISO date, Unix seconds or Unix milliseconds. Use current time inserts the device clock value.
3. Valid input updates after a brief typing pause. You can also use the main action button. Resolve errors before copying or downloading.
4. Clear input keeps the conversion settings; Undo input change restores the previous inputs after clear or reverse. Reset restores the example and default settings.

Understanding the output

Unix time counts elapsed units from 1970-01-01T00:00:00Z. The output always shows UTC, avoiding dependence on the device’s local timezone. Fractional milliseconds are not accepted as timestamp input; ISO input can include up to three fractional-second digits.

If a timestamp appears inside a data payload, use the JSON Formatter to locate the field before converting its value.

Check the unit before diagnosing the date

An epoch value in milliseconds is much larger than one in seconds for the same moment. Interpreting a millisecond value as seconds can produce a date far outside the intended period, while interpreting seconds as milliseconds can place a modern event close to 1970. The tool requires an explicit unit instead of guessing from the number of digits.

Negative values represent times before the epoch. A timestamp is an instant, not a timezone label; a local clock representation depends on the timezone applied when displaying that instant.

Make timezone information explicit

A date string without a timezone can be interpreted differently by different systems. This converter requires Z or a numeric offset so the instant is unambiguous. It also rejects invalid calendar days rather than allowing a date such as February 30 to roll into the following month. Leap-second notation is outside the supported JavaScript date model.

Method and supported input

Integer timestamps are scaled to milliseconds and converted with the JavaScript Date API. ISO inputs undergo calendar checks before parsing, and the result is serialized as UTC.

A single-format result is suitable for copying as a value without report labels. Unix seconds can include a fractional part when ISO input contains milliseconds; numeric timestamp input still requires an integer.

• The epoch uses the conventional JavaScript/Unix representation without explicit leap seconds.

Limitations

• Supported dates are limited by JavaScript Date and safe integer input.
• Named timezones and daylight-saving rules are not accepted as input; use an explicit offset.

Common questions