Unix time starts on 1 January 1970 because that date was chosen as the "Unix epoch" — the zero point from which seconds are counted — by the engineers building Unix at Bell Labs in the early 1970s. It has no cosmic meaning; it was simply a convenient, recent round date, and counting seconds from a single fixed moment makes time math simple and free of time zones. Every timestamp you see, like 1786000000, is just "this many seconds after that 1970 zero point."
If you've ever wondered why computers seem obsessed with 1970 — why a broken date defaults to "1 Jan 1970" and why timestamps count from there — this is the story. You can see the current count ticking live, or convert any timestamp to a real date, with our free Unix Timestamp Converter.
The short history: Bell Labs, early 1970s
Unix was created at Bell Labs starting around 1969 by Ken Thompson, Dennis Ritchie and their colleagues. Early versions needed a way to store time as a simple number, so they picked a starting point — an epoch — and counted forward from it.
The first choice wasn't even 1970. Early Unix measured time in sixtieths of a second (matching the electrical grid's 60 Hz) and used an epoch of 1 January 1971. The problem: at 60 ticks per second, a 32-bit counter overflows in only about 2.5 years — the clock would run out almost immediately. So the team made two changes: they switched to counting whole seconds instead of sixtieths, and they moved the epoch back to the round date of 1 January 1970, 00:00:00 UTC. Counting seconds instead of sixtieths stretched the same 32-bit counter to last until 2038 instead of 1973.
