Timestamp Converter

Convert between Unix epoch time and human dates — seconds or milliseconds auto-detected, UTC and local side by side.

current epoch seconds milliseconds

Type an epoch timestamp (seconds or milliseconds — detected automatically) or a date like 2026-12-25 09:00.

unix time 101

What Unix time is

Unix time counts the seconds since 1970-01-01 00:00:00 UTC — "the epoch." It's a single ever-increasing number with no timezone, no daylight-saving, no calendar quirks, which is exactly why systems use it internally and convert to human dates only at the edges. Epoch 0 is the moment itself; negative numbers reach back before 1970.

Seconds, milliseconds, and friends

The same instant appears at different magnitudes depending on the ecosystem, and mixing them up produces dates in 1970 or the year 55978:

unit	digits today	where you'll see it
seconds	10	Unix tools, Python `time.time()` (as a float), C `time_t`, JWT `exp`
milliseconds	13	JavaScript `Date.now()`, Java, many APIs and log formats
microseconds	16	databases (PostgreSQL internals), some tracing systems
nanoseconds	19	Go `UnixNano()`, Prometheus, kernel timestamps

This tool auto-detects seconds vs milliseconds by digit count (12+ digits ⇒ milliseconds). For micro/nano, divide by 1,000 or 1,000,000 first.

The year 2038 problem

A signed 32-bit time_t overflows at 2,147,483,647 — 2038-01-19 03:14:07 UTC — wrapping to 1901. Modern 64-bit systems are fine for 292 billion years, but embedded devices, old file formats, and legacy databases still carry the fuse. Paste 2147483647 above to meet the moment.

Quirks worth knowing

No leap seconds — Unix time pretends every day is exactly 86,400 seconds. When a leap second happens, clocks smear or repeat; epoch arithmetic stays simple and slightly a lie.
Timezones are a display problem — an epoch value is absolute. "The same timestamp shows different clock times in different places" is correct behavior, not a bug. Store epochs (or ISO 8601 with offset); format late.
Bare dates are ambiguous — 2026-12-25 parses as midnight UTC per the ISO standard, but December 25, 2026 parses as midnight local in most libraries. When it matters, write the offset.
Handy commands — Linux: date -d @1234567890 and date +%s. PowerShell: Get-Date -UnixTimeSeconds 1234567890 and [DateTimeOffset]::Now.ToUnixTimeSeconds().