Unix Epoch: What Is Timestamp 0?
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 Unix timestamp converter already set to 0, the Unix epoch — the moment Unix time began counting. The decoded date, January 1, 1970, 00:00:00 UTC, appears immediately, converted into your selected time zone.
Unix time measures elapsed seconds since that instant, so timestamp 0 is not an arbitrary placeholder — it is the fixed reference point every other Unix timestamp is counted from. A negative timestamp represents a moment before 1970; a positive one, a moment after.
Edit the timestamp field to convert any other value, in seconds or milliseconds, or edit the date and time fields instead to go the other direction and generate a Unix timestamp for a moment you choose. Everything is computed locally using your browser’s own date engine.
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.