Epoch Converter

Convert Unix seconds and milliseconds to UTC and back. Your local time zone is labeled next to UTC.

Direction *

Unit *

Unix timestamp *

Smart Tips

• 0 seconds and 0 milliseconds are both 1970-01-01 00:00:00.000 UTC.

• 1,000 milliseconds is 1 second.

• Each UTC day on this page is 86,400 seconds. Leap seconds are not inserted.

• The local line uses your browser zone and names that zone.

• A time zone page does not take a Unix timestamp. This one does.

The Formula

seconds = days since 1970-01-01 UTC × 86400 + hour×3600 + minute×60 + second

epoch1970-01-01 00:00:00 UTC, which is timestamp 0.

86400Seconds in one UTC day. Leap seconds are not added.

msMilliseconds = seconds × 1000.

localThe same instant shifted by your zone offset, with the zone name.

February 29, 1972 00:00:00 UTC is 68,169,600 seconds, which is 789 days after the epoch.

Key Insights

Both units

Switch the unit to read the same instant as seconds or as milliseconds.

UTC first

The large figure is UTC. Local time is a second line, with the zone name.

Leap day

1972-02-29 is a real Unix day. 1900-02-29 is not a valid date.

No leap second

POSIX counts every day as 86400 seconds, so this page does too.

Frequently Asked Questions

0 seconds and 0 milliseconds are both 1970-01-01 00:00:00.000 UTC. That instant is the epoch.

Multiply seconds by 1,000. Timestamp 1,000 milliseconds is 1970-01-01 00:00:01.000 UTC. The page converts either unit in both directions.

No. Every UTC day is 86,400 seconds, which is the POSIX rule for seconds since the epoch. A leap second is not given its own count.

The conversion itself is UTC. The page also shifts that instant by your browser’s offset and prints the IANA zone name next to it, so you can see both readings.

Yes. The day count is the proleptic Gregorian calendar extended backward. POSIX leaves negative values undefined; this page still shows them, including 1969-12-31 for a negative offset from the epoch.

POSIX defines seconds since the Epoch as whole days of 86400 seconds from 1970-01-01 00:00:00 UTC and does not insert leap seconds. Milliseconds are that count times 1,000. pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html

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UTC

Enter a timestamp or a UTC date

Seconds

Milliseconds

Local time

Note:Unix time here is seconds or milliseconds since 1970-01-01 00:00:00 UTC. Each day is 86400 seconds. Leap seconds are not inserted. Your local zone is labeled beside the UTC time.