ClockMath

Unix Timestamp Converter

Paste a Unix timestamp on the left (seconds, ms, µs, or ns) or pick a date on the right. Every unit appears in the result, including the equivalent C# ticks for cross-platform work.

How this works

A Unix timestamp counts the seconds since the epoch, 1970-01-01 00:00:00 UTC. To convert to a calendar date you divide by 86,400 to get the day number, then handle months and years from there — the proleptic Gregorian calendar makes this deterministic. In practice every language ships a built-in: JavaScript's new Date(ms), Python's datetime.fromtimestamp(s, tz=UTC), .NET's DateTimeOffset.FromUnixTimeSeconds(s).

This converter canonicalises every input to BigInt nanoseconds so values pasted at microsecond or nanosecond precision don't lose their lower digits during round-trips.

Common examples

  • 0Unix epoch (1970-01-01 UTC)
  • 1000000000September 9, 2001 (the famous billion-second mark)
  • 1234567890February 13, 2009 — 1234567890 seconds
  • 1714564800May 1, 2024 12:00 UTC
  • 2147483647Year 2038 problem (max int32 seconds)

Frequently asked questions

What is a Unix timestamp?

A Unix timestamp is the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC, ignoring leap seconds. Variants use milliseconds, microseconds, or nanoseconds for more precision.

How do I know if my timestamp is in seconds, milliseconds, microseconds, or nanoseconds?

Count the digits. A modern timestamp (post-2001) has about 10 digits in seconds, 13 in milliseconds, 16 in microseconds, and 19 in nanoseconds. This converter auto-detects the unit when you paste a value into the permalink URL, and the unit selector lets you override it.

What is the year 2038 problem?

Many older systems store Unix timestamps as a signed 32-bit integer. That overflows at 2147483647 seconds, which is 2038-01-19 03:14:07 UTC. Beyond that, the timestamp wraps to a negative number and dates jump back to 1901. Modern systems use 64-bit integers, which won't overflow for ~292 billion years.

Do Unix timestamps account for timezones?

No. A Unix timestamp identifies a single instant in time, equivalent in every zone. The date you display depends on which timezone you format it in. Use the timezone selector in this converter to render the same instant in any zone.

Does this converter handle leap seconds?

Like virtually all software, no. Unix time intentionally ignores leap seconds — a Unix day is always exactly 86,400 seconds, even though the actual mean solar day occasionally includes an extra second.

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