What a Unix timestamp counts
Unix time counts seconds from midnight UTC on 1 January 1970, ignoring leap seconds. A value of 1793275200 is 20,755 whole days after that moment.
Because the count is always UTC, the same number means the same instant everywhere. Only the offset you display it at changes.
Worked example
The timestamp 1793275200 is 29 October 2026, 12:00:00 UTC, which is a Thursday and 20,755 days after the epoch. At an offset of +5.5 hours the same instant reads 29 October 2026, 17:30:00 UTC+05:30.
The ISO 8601 form is 2026-10-29T12:00:00.000Z, where the Z means UTC.
Seconds, milliseconds and time zones
Some systems store milliseconds rather than seconds. A 13-digit value is almost always milliseconds, so divide by 1,000 before entering it here.
Offsets are not the same as time zone names. A zone such as Europe/London is UTC in winter and UTC+1 in summer, so enter the offset that applies on the date you are converting.
Limits of this calculator
It converts one timestamp at a time and does not apply daylight saving automatically, because a fixed offset cannot know the rule for a region.
It does not handle leap seconds, and it does not convert a date back into a timestamp.
For another unit conversion, use the data calculator.
Inputs for the epoch calculator
Unix timestamp
Whole seconds since 1 January 1970 UTC. A 13-digit value is milliseconds and needs dividing by 1,000.
UTC offset to show
Hours ahead of or behind UTC, such as 5.5 for India or -5 for New York.
CALCULATOR QUESTIONS
Epoch calculator questions
Why is my timestamp 13 digits?
It is in milliseconds. Divide by 1,000 to get the seconds this page expects.
Does this handle daylight saving?
No. It applies the offset you type, so use the offset in force on that date.
What does the Z mean in an ISO date?
Zero offset, meaning UTC. 2026-10-29T12:00:00Z and 2026-10-29T12:00:00+00:00 are the same instant.
What happens before 1970?
The timestamp is negative. This page accepts negative values.