Unix Timestamp Converter

Unix time (epoch time) counts elapsed seconds since 00:00:00 UTC on January 1, 1970 — the Unix epoch. It is a single integer with no timezone or calendar embedded in it at all, which is exactly why it is the default timestamp format for databases, logs, and APIs: it sorts numerically, compares cleanly, and never needs disambiguating across timezones the way a written date does.

Where it gets confusing is precision. The Unix standard is seconds, but almost nothing that touches JavaScript stays in seconds — Date.now()and every JS timestamp return milliseconds, because a second is too coarse for measuring anything on a computer. Java’s System.currentTimeMillis()follows the same convention. Meanwhile a growing set of databases and APIs, particularly ones built for high-resolution event data, emit microseconds instead. Three units, all called “a timestamp,” all just an integer — so the same 13-digit number can mean either “milliseconds since 1970” or, read under the wrong assumption, an event from tens of thousands of years in the future.

This tool resolves that ambiguity by magnitude rather than by counting digits, which holds up better for old or far-future dates than a fixed digit-count rule does. If the auto-detected unit is wrong for your specific data, the “treating as…” chip next to the timestamp field is directly editable — click seconds, milliseconds, or microseconds to override it, and every output row updates immediately.

Everything below runs in your browser using the platform’s built-in Date and Intl objects — no timestamp you paste here is sent anywhere.