Unix Timestamp Converter

Unix Timestamp Converter — Epoch Time Explained for Developers

A Unix timestamp is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970 — a reference point known as the Unix epoch. It is the most widely used method for storing and transmitting date and time information in software systems, precisely because it is timezone-independent, format-independent and trivially comparable. Two timestamps can be subtracted to find a duration; one can be compared to another with a simple greater-than check; and any programming language can convert one to a human-readable date in a single function call.

Unix timestamp to date converter online free

Converting a Unix timestamp to a human-readable date requires dividing by the appropriate unit (timestamps are often stored in milliseconds rather than seconds in JavaScript and Java), then constructing a date object. The resulting date is in UTC by default — converting to a local or specific timezone requires knowing the UTC offset for that zone at that point in time, which varies due to daylight saving time. This tool handles all of that automatically and shows the result in nine major timezones simultaneously.

Epoch milliseconds to datetime converter

The most common source of confusion when working with Unix timestamps is the unit. JavaScript’s Date.now() and new Date().getTime() both return milliseconds. Python’s time.time() returns seconds as a float. PostgreSQL’s EXTRACT(EPOCH FROM NOW()) returns seconds. MySQL’s UNIX_TIMESTAMP() returns seconds. Java’s System.currentTimeMillis() returns milliseconds. A 13-digit number is almost certainly milliseconds; a 10-digit number is almost certainly seconds. Converting milliseconds to a date without dividing by 1000 first produces a date in 2526 rather than 2026 — a common debugging puzzle.

Current Unix timestamp with timezone

The live ticker in this tool shows the current Unix timestamp in both seconds and milliseconds, updating every second. This is useful when you need to copy the current time as a timestamp for use in a database query, an API call body, a log entry or a debugging session. The ticker value is equivalent to running Date.now() in a browser console or int(time.time()) in a Python shell.

ISO 8601 date format converter

ISO 8601 is the international standard for date and time representation, widely used in APIs, databases and data interchange formats. The format is YYYY-MM-DDTHH:MM:SSZ (the Z indicates UTC) or YYYY-MM-DDTHH:MM:SS+HH:MM for a specific timezone offset. ISO 8601 is the format returned by JavaScript’s new Date().toISOString(), Python’s datetime.utcnow().isoformat() and most REST APIs. This tool shows the ISO 8601 representation of any converted timestamp so it can be pasted directly into API requests or database inserts.

The Year 2038 problem

The Unix timestamp 2147483647 — equivalent to 19 January 2038 at 03:14:07 UTC — is the maximum value representable by a 32-bit signed integer. Systems that store timestamps as 32-bit signed integers will overflow on this date, wrapping to a large negative number and typically displaying a date in 1901. This is analogous to the Year 2000 bug. Modern systems use 64-bit integers which extend the representable range to the year 292 billion CE — well beyond any practical concern. The solution for legacy systems is to migrate timestamp storage from INT(11) to BIGINT in databases, and from int32_t to int64_t or time_t in C/C++ code.

Python datetime from timestamp

In Python, converting a Unix timestamp to a datetime object uses datetime.fromtimestamp(ts) for local time or datetime.utcfromtimestamp(ts) for UTC. Converting a datetime to a Unix timestamp uses datetime.timestamp() in Python 3.3+ or calendar.timegm(dt.timetuple()) for UTC datetimes in older versions. The arrow and pendulum libraries provide more ergonomic timezone-aware datetime handling and are preferred in production code over the standard library datetime module for complex timezone work.

Frequently asked questions