DateDelta

Unix Timestamp Calculator

The number format behind database timestamps, API responses, and log files.

Date and time (local)

Unix timestamps for notable dates

A Unix timestamp counts seconds since midnight UTC on 1 January 1970, the epoch.

Date (UTC)	Unix timestamp	Note
1 January 1970	0	The epoch itself
1 January 2000	946684800	Millennium
1 January 2020	1577836800	Start of the decade
1 January 2026	1767225600	Current era
19 January 2038	2147472000	Near the 32-bit limit

The 2038 row is the reason this matters: a signed 32-bit integer overflows at 2,147,483,647 seconds, which falls on 19 January 2038, after which such systems wrap to a negative number and read 1901. Modern systems use 64-bit timestamps and are safe for roughly 292 billion years, but embedded and legacy code remains a real concern. Timestamps are always UTC, so converting to a local date requires applying the offset and any daylight saving in force on that date - which is why storing timestamps rather than local times avoids a whole class of bug.

Why the epoch is 1970

January 1, 1970 UTC was chosen somewhat arbitrarily by early Unix developers as a convenient reference point — it predates almost no real-world data that mattered to early computing, and the math works out to fit comfortably in a 32-bit integer for decades.

The Year 2038 problem

Systems that store Unix time as a signed 32-bit integer will overflow on January 19, 2038 — a real, if increasingly rare, legacy-software concern, similar in spirit to the Y2K bug, that modern 64-bit systems have already resolved.

Frequently asked questions

What's the Unix timestamp for January 1, 2025 at midnight UTC?

1,735,689,600. That's 1.74 billion seconds since the epoch (January 1, 1970 00:00:00 UTC). Enter the date above and the exact timestamp appears instantly.

I see '1693526400' in a database field — what date is that?

Enter the timestamp above in reverse mode: 1,693,526,400 seconds after the epoch = September 1, 2023 00:00:00 UTC. Most APIs and databases store timestamps this way because integers sort, compare, and subtract much faster than date strings.

Why do some timestamps have 13 digits instead of 10?

A 13-digit timestamp is in milliseconds (not seconds). JavaScript's Date.now() returns milliseconds. To convert, divide by 1,000. Timestamp 1693526400000 (13 digits) = 1693526400 (10 digits) = September 1, 2023.

Will the Y2K38 bug actually cause problems?

Most modern systems use 64-bit timestamps (good until the year 292 billion). But embedded systems, legacy databases, and some IoT devices still use 32-bit timestamps and will overflow on January 19, 2038. It's a real concern for long-lived infrastructure — not catastrophic, but requires migration planning.