Unix Timestamp Converter
Convert a Unix timestamp to a human-readable UTC date and time — with automatic detection of millisecond timestamps.
How it works
date = January 1, 1970 00:00 UTC + timestamp seconds
Unix time counts seconds since the "epoch" — midnight UTC on January 1, 1970 — ignoring leap seconds. It is the standard clock inside operating systems, databases and APIs because a single integer is easy to store and compare. Many platforms use milliseconds instead, giving 13-digit numbers; this converter assumes seconds and switches to milliseconds when the value exceeds 10¹², since a 13-digit second count would be tens of thousands of years away.
Worked example
Timestamp 1789000000: that is 56.69 years after the epoch, landing on Thursday, September 10, 2026 at 00:26:40 UTC. The same moment in milliseconds would be written 1789000000000.
Frequently asked questions
Why does my timestamp show a date in 1970?
A tiny value (or 0) sits right at the epoch — often a sign that a system stored "no date" as zero. And a millisecond value mistakenly read as seconds does the reverse, throwing dates 50,000+ years into the future; the auto-detection here guards against that.
What is the year-2038 problem?
Timestamp 2,147,483,647 (January 19, 2038) overflows a signed 32-bit integer, the type old systems store Unix time in. Modern 64-bit timestamps push the limit billions of years out, but embedded and legacy systems still need patching.
Do timestamps have time zones?
No — a Unix timestamp is always UTC; the same instant everywhere on Earth. Local time is applied only at display time, which is exactly why timestamps are the safe way to store moments.
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This calculator is for educational purposes. Double-check important results before acting on them.