Unix Time Converter
Convert Unix timestamp (seconds or milliseconds) to human-readable date and time. Free, instant. Supports both Unix seconds and Unix milliseconds.
What is Unix time?
Unix time (also called epoch time or POSIX time) is a way to represent a point in time as a single number: the number of seconds or milliseconds that have passed since January 1, 1970, 00:00:00 UTC. That starting moment is called the Unix epoch. For example, the Unix timestamp 0 means “1970-01-01 00:00:00 UTC”; one hour later is 3600 in seconds.
Unix time is used in operating systems (e.g. Linux file timestamps), databases, APIs, and logs because it is a single number that is easy to store, compare, and sort. It also avoids time zone and daylight-saving confusion as long as you convert to a human-readable format at display time.
Seconds vs milliseconds
Unix seconds: the count of whole seconds since the epoch. Typically a 10-digit number (e.g. 1737123456). Used in many Unix-like systems, in APIs (e.g. some REST APIs return “created_at” in seconds), and in languages like C, Python, or PHP when using epoch-based functions.
Unix milliseconds (also called “Unix timestamp in ms” or “milliseconds since epoch”): the same idea, but in milliseconds. Usually a 13-digit number (e.g. 1737123456000). JavaScript’s Date.now() and new Date().getTime() return milliseconds; some APIs (e.g. Stripe, many JSON APIs) also use milliseconds. One second = 1,000 milliseconds, so the same moment in time can be written as 1737123456 (seconds) or 1737123456000 (milliseconds).
This tool lets you choose the unit (second or millisecond), enter the number, and see the corresponding date and time in your local time zone and in ISO 8601 (UTC). The “Now” button fills in the current time in the selected unit.
Jan 1, 1970 00:00:00 UTC ← — — — — — — — — — — — — — — — — — — — — — → Present
Whole seconds since epoch. Used in many systems (Linux, APIs).
e.g. 1737123456
≈ 10 digits
Milliseconds since epoch. Used in JavaScript (Date.now()), some APIs.
e.g. 1737123456000
≈ 13 digits
Same moment: 1737123456 (seconds) = 1737123456000 (milliseconds)
Time zones and display
Unix time is always defined in UTC (Coordinated Universal Time). There is no daylight saving or time zone inside the number itself. When we convert to a “human” date and time, we show:
- Local time: the date and time in your browser’s time zone (e.g. Seoul, New York).
- ISO 8601 (UTC): the same moment in UTC, in the standard format (e.g. 2025-01-17T12:30:00.000Z).
We also show the same moment expressed again as seconds and as milliseconds, so you can copy the value in either unit.