Unix Timestamp Converter

Convert a Unix timestamp to a UTC date.

Unix timestamp (seconds)

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UTC date and time

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Weekday—

How it works

A Unix timestamp converter turns a count of seconds since the Unix epoch — midnight UTC on 1 January 1970 — into a human-readable UTC date and time, and names the weekday. Unix time, also called epoch or POSIX time, is how most computers, databases, APIs and log files store an instant, because a single integer is compact, unambiguous and easy to compare or subtract. Developers and analysts constantly meet raw timestamps like 1609459200 in logs, JSON payloads, database rows and cookies, and need to know what moment they represent. Converting by hand is impractical, and doing it in the wrong timezone is a frequent source of off-by-hours bugs. Presenting the result explicitly in UTC removes that ambiguity: UTC is the reference the epoch is defined against, so the conversion is exact and location-independent. The weekday is a useful extra for spotting patterns in event data, such as whether errors cluster on weekends or a job ran on the expected day. This converter takes whole seconds, the most common form, though some systems store milliseconds; if a value looks a thousand times too large, divide by 1000 first. Engineers debugging systems, data analysts reading exports, and anyone decoding an API response use a Unix timestamp converter to translate machine time into a date they can reason about.

Formula

UTC datetime = 1970-01-01 00:00:00 UTC + unixSeconds seconds

The Unix epoch fixes second zero at midnight UTC on 1 January 1970. Adding the given number of seconds to that anchor point yields the target instant, which is then expressed on the UTC calendar as year, month, day, hour, minute and second. Because leap years and month lengths are built into the calendar conversion, and UTC ignores daylight-saving shifts, the result is exact and identical no matter where or when the conversion is run.

Source:ISO 8601 / Unix epoch (POSIX time)

We review all our tools from time to time to ensure accuracy.

Worked example

Unix timestamp (seconds):1609459200

1609459200 seconds is 2021-01-01 00:00:00 UTC, a Friday.

How to use this calculator

1
Enter your values
Enter unix timestamp (seconds).
2
Adjust the options
Fine-tune any options to match your situation.
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Read your result
UTC date and time updates instantly as you type — no button to press.

Frequently asked questions

What is a Unix timestamp?

A Unix timestamp is the number of seconds that have elapsed since the Unix epoch, midnight UTC on 1 January 1970, not counting leap seconds. It is the standard way computers represent a point in time, because storing an instant as one integer makes it compact and trivial to compare or subtract. Timestamps appear throughout logs, databases, APIs and file metadata, which is why converting them to dates is a routine task.

Why is the result shown in UTC?

The Unix epoch is defined in UTC, so converting to UTC is exact and free of timezone or daylight-saving ambiguity. Showing a local time would require assuming a timezone, which invites off-by-hours errors when the same timestamp is read in different regions. If you need local time, take the UTC result and apply your own zone's offset, remembering that the offset can change across daylight-saving boundaries.

My timestamp has 13 digits — what do I do?

A 13-digit value is almost certainly in milliseconds rather than seconds, which many JavaScript and Java systems use. Divide it by 1000 to get seconds before entering it here, dropping any fractional part. As a rule of thumb, a seconds-based timestamp for a recent date has about 10 digits; a 13-digit number is a thousand times larger and would otherwise convert to a date far in the future.

What was timestamp zero?

Timestamp 0 corresponds to 1970-01-01 00:00:00 UTC, the moment the Unix epoch begins, which fell on a Thursday. Negative timestamps, where supported, represent times before 1970. This fixed origin is what makes Unix time a universal reference: every system counting from the same instant can exchange timestamps without needing to agree on anything else about the calendar.

Does this account for leap seconds?

No, and by design. Standard Unix time ignores leap seconds, treating every day as exactly 86,400 seconds, which is why it converts cleanly to a calendar date. Occasional leap seconds inserted into UTC mean Unix time can be a second out of step with astronomical time around those events, but for everyday date conversion this has no practical effect and the result matches the civil calendar.