Unix Timestamp Converter
Convert epoch seconds to datetime or datetime to epoch seconds, all in your browser.
Convert between Unix timestamps (epoch seconds) and human-readable dates. Supports UTC and JST. Runs entirely in your browser.
Unix Timestamp Converter
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What is a Unix Timestamp?
A Unix timestamp (epoch time) is the number of seconds elapsed since the Unix epoch — 1 January 1970, 00:00:00 UTC — represented as an integer. For example, "1710000000" means 2024-03-10 00:00:00 UTC. It is a universal time representation used across operating systems and programming languages.
A 10-digit value represents seconds; a 13-digit value represents milliseconds. JavaScript's Date.now() returns milliseconds, while Python's time.time() and the Unix command date +%s return seconds.
Negative values
Dates before 1 January 1970 are represented as negative timestamps. For example, "-86400" corresponds to 1969-12-31 00:00:00 UTC.
Why Engineers Use Unix Timestamps
Date strings come in many formats — "2024/03/10", "March 10, 2024", "10-03-2024" — leading to parsing errors and inconsistencies. A Unix timestamp is a plain integer, uniquely representing a moment in time regardless of language, OS, or timezone, making it ideal for inter-system data exchange.
Easy time arithmetic
Simply subtract two timestamps to get the elapsed seconds. Operations like "3600 seconds later" or "86400 seconds ago" are straightforward to express in code, making Unix timestamps ideal for log analysis, expiry checks, and sorting.
Storage and transmission efficiency
An integer timestamp fits neatly into a database integer column or JSON field and takes less space than a datetime string. Unix timestamps are also used in REST APIs and JWT claims (exp, iat) for the same reason.
How to Use This Tool
Epoch → Datetime mode
Enter a Unix timestamp in seconds (10 digits) or milliseconds (13 digits) to instantly see the UTC, JST, and relative time. Click "Now" to fill in the current epoch. Each result can be copied to the clipboard via the copy icon on the right.
Datetime → Epoch mode
Enter a datetime and timezone to calculate the corresponding Unix timestamp in seconds and milliseconds in real time. Timezones can be entered as "+09:00", "UTC-5", "JST", and so on. You can also pick a common timezone from the dropdown.
Copy button
Click the copy icon at the right end of any result row to copy the value to your clipboard — handy for pasting into API parameters or debug sessions.