Unix epoch time (also called a Unix timestamp or POSIX time) is a way of representing time as a single number: the total number of seconds elapsed since January 1, 1970, 00:00:00 UTC, known as the Unix epoch. It does not account for leap seconds and is timezone-independent, making it a universal standard for representing moments in time across different systems and programming languages.
For example, the Unix timestamp 1700000000 corresponds to Tue, 14 Nov 2023 22:13:20 UTC.
To convert a Unix timestamp to a human-readable date, divide the timestamp by the appropriate unit (1 for seconds, 1000 for milliseconds) and pass it to a date/time function in your language of choice. Epochify handles this instantly: paste the timestamp, select your timezone and unit, and hit Convert.
from datetime import datetime, timezone
dt = datetime.fromtimestamp(1700000000, tz=timezone.utc)
print(dt) # 2023-11-14 22:13:20+00:00const date = new Date(1700000000 * 1000);
console.log(date.toUTCString()); // Tue, 14 Nov 2023 22:13:20 GMTSELECT TO_TIMESTAMP(1700000000);Going the other direction is equally common. You may need to convert a known date to its epoch value for storage, comparison, or sending in an API request.
from datetime import datetime, timezone
dt = datetime(2023, 11, 14, 22, 13, 20, tzinfo=timezone.utc)
print(int(dt.timestamp())) # 1700000000const epoch = Math.floor(new Date('2023-11-14T22:13:20Z').getTime() / 1000);
console.log(epoch); // 1700000000Epoch timestamps are preferred in software development for several reasons:
While the original Unix timestamp counts in seconds, many modern systems use finer resolutions:
Date.now(), Java, and most REST
APIs. Divide by 1,000 to get seconds.Epochify supports all three. Just select the correct unit before converting.
Unix timestamps appear across nearly every layer of modern software. Below are situations where developers, DevOps engineers, and analysts encounter them daily.
created_at or updated_at instead of a native datetime, particularly in SQLite and older MySQL versions.iat, exp, and nbf claims in JSON Web Tokens are Unix timestamps in seconds.The table below shows well-known timestamps and their human-readable equivalents in UTC.
| Timestamp | Date & Time (UTC) | Note |
|---|---|---|
| 0 | Thu, 01 Jan 1970 00:00:00 | The Unix epoch |
| 1000000000 | Sun, 09 Sep 2001 01:46:40 | One billion seconds |
| 1234567890 | Fri, 13 Feb 2009 23:31:30 | Ascending digit sequence |
| 1500000000 | Fri, 14 Jul 2017 02:40:00 | 1.5 billion seconds |
| 1700000000 | Tue, 14 Nov 2023 22:13:20 | 1.7 billion seconds |
| 2000000000 | Wed, 18 May 2033 03:33:20 | Two billion seconds |
| 2147483647 | Tue, 19 Jan 2038 03:14:07 | 32-bit signed integer maximum |
Many older systems store Unix timestamps as a signed 32-bit integer. The largest value a signed 32-bit integer can hold is 2,147,483,647, which corresponds to Tuesday, 19 January 2038 at 03:14:07 UTC. One second later the value overflows to a large negative number, causing the system to interpret the date as December 1901.
This is sometimes called the Y2K38 bug or the Epochalypse. It mirrors the Year 2000 problem but affects low-level infrastructure rather than display formatting.
TIMESTAMP columns have an upper bound of 2038-01-19. Newer versions and PostgreSQL use 64-bit storage.time_t as a 32-bit type will overflow. Most modern 64-bit compilers already define time_t as 64-bit.Use 64-bit timestamps wherever possible. In databases, prefer BIGINT or native TIMESTAMPTZ columns. In application code, ensure your language runtime uses 64-bit epoch values — Python, Java, Go, and modern C compilers on 64-bit systems already do this by default. Audit any third-party libraries or file formats that may still assume 32-bit storage.
Unix epoch time is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. It provides a single, timezone-independent integer that any system can interpret without formatting rules.
The date was chosen by the designers of early Unix at Bell Labs. It was a recent, round date at the time the system was being developed, and using midnight UTC on the first day of the year simplified calculations.
No. POSIX time assumes every day has exactly 86,400 seconds. When a leap second is inserted by international timekeeping authorities, Unix clocks either repeat a second or use a "smeared" adjustment. This means a Unix timestamp does not correspond exactly to TAI or UTC during a leap second event.
They differ only in resolution. A timestamp of 1700000000 in seconds equals 1700000000000 in milliseconds and 1700000000000000 in microseconds. JavaScript's Date.now() returns milliseconds; Python's time.time() returns seconds as a float; PostgreSQL's clock_timestamp() gives microsecond precision.
Yes. A negative timestamp represents a moment before the epoch. For example, -86400 is December 31, 1969, 00:00:00 UTC. Not all systems support negative timestamps — some treat the value as unsigned or clamp it to zero.
In a terminal: date +%s (Linux/macOS). In Python: import time; time.time(). In JavaScript: Math.floor(Date.now() / 1000). Or simply look at the live counter at the top of this page.
Systems using a signed 32-bit integer for timestamps will overflow on January 19, 2038. Most modern platforms use 64-bit integers, which will not overflow for approximately 292 billion years. See the Year 2038 Problem section above for details.
Yes. The web converter and API are free with no account required. API requests are rate limited to 60 per minute per IP to keep the service available for everyone.