Unix Timestamp to Date Converter
Convert a local date and time in a chosen IANA zone to Unix seconds, or read a seconds or milliseconds value back.
Processed entirely in your browser — nothing you enter here is ever uploaded.
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About this tool
This page opens the converter focused on the direction most people need when they already have a raw number from a log file, database column, or API response: turning a Unix timestamp back into a readable date.
Paste the timestamp into the value field and the calculator decodes it immediately, showing the date and time in the time zone you select, along with an exact ISO 8601 representation for precise reference.
The decoder automatically distinguishes second-based timestamps from millisecond-based ones by magnitude, which avoids the most common conversion mistake — reading a millisecond value as if it were seconds and landing on a date decades off.
Example. The number 0 is 1970-01-01T00:00:00.000Z. The number 1700000000 is read as seconds and is 2023-11-14T22:13:20.000Z. The number 1700000000000 is read as milliseconds and is the same instant.
Limit. A finite number whose absolute value is below 100,000,000,000 is seconds. Any larger absolute value is milliseconds. A wall time that falls in a daylight-saving gap is rejected.