Unix 时间戳转换器

What is a Unix timestamp?

A Unix timestamp is the number of seconds since 00:00:00 UTC on 1 January 1970 — the moment commonly called the Unix epoch. It is a single integer, which makes it trivial to store, compare and sort.

Seconds vs milliseconds

This is the most common source of confusion:

• 10 digits (e.g. 1736899200) — seconds
• 13 digits (e.g. 1736899200000) — milliseconds

JavaScript's Date.now() returns milliseconds, while Math.floor(Date.now() / 1000) returns seconds. This tool detects the difference automatically from the digit count.

Common formats

The 2038 problem

The Unix epoch is near its upper limit for 32-bit signed integers: 19 January 2038. Systems storing timestamps as 32-bit integers will overflow around then. If you maintain software that will still be running, use 64-bit integers or ISO 8601 strings.

Timezone notes

Unix timestamps are always UTC. The tool shows both the UTC value and your browser's local time so you can confirm the conversion. Daylight saving shifts are handled automatically by your local timezone.