Unix Timestamp Converter Free Online

Free online Unix timestamp converter. Convert Unix timestamp to human readable date, or convert date to Unix timestamp instantly.

Current Unix Timestamp

What is Unix time?

Unix timestamp counts seconds since January 1, 1970 00:00:00 UTC (the “epoch”). Most programming languages and databases use this format internally.

Unix timestamps appear everywhere in software development - in API responses, database records, log files, JWT tokens, file system metadata, and event tracking systems. A Unix timestamp is simply the number of seconds (or milliseconds) that have elapsed since 1 January 1970 00:00:00 UTC, known as the Unix epoch. This free timestamp converter instantly translates Unix timestamps to human-readable dates and times, and converts dates back to timestamps, in both seconds and milliseconds formats.

How to Use the Unix Timestamp Converter

1

Enter a Unix timestamp

Paste or type a Unix timestamp into the input field. The converter automatically detects whether the timestamp is in seconds (10 digits, like 1700000000) or milliseconds (13 digits, like 1700000000000). Both formats are supported and detected automatically. You can also click the "Now" button to get the current timestamp.

2

View the human-readable date

The equivalent date and time is shown instantly in multiple formats: your local timezone, UTC, and ISO 8601 format. The local timezone is detected from your browser settings so you see the date as it would appear in your location. Both the date and time are shown with full precision including the day of the week.

3

Convert a date to a timestamp

Switch to the date-to-timestamp mode and use the date picker to select a specific date and time. The converter shows the corresponding Unix timestamp in both seconds and milliseconds. This is useful for constructing date range queries, setting expiration times, or working with API parameters that require timestamps.

What Is the Unix Epoch and Why 1970?

The Unix epoch is January 1, 1970, 00:00:00 UTC - the starting point from which Unix time is measured. This date was chosen somewhat arbitrarily in the early days of Unix development in the late 1960s and early 1970s. It was a convenient recent date that would work well for the expected timespan of computing, and it has since become the universal standard for computer time representation.

Before Unix timestamps, different systems used different date reference points, making it difficult to synchronise time between systems. Unix timestamps solved this by providing a single universal integer that unambiguously represents any moment in time, regardless of timezone or locale. Any system that knows the Unix epoch can convert a timestamp to a local date/time.

Seconds vs Milliseconds Timestamps

Two versions of Unix timestamps are commonly encountered in software development:

Unix timestamp in seconds - the original format, a 10-digit number (as of 2024). For example, 1700000000 represents November 14, 2023. This is used in most server-side languages (Python, PHP, Ruby, Go, Rust) and in the Unix/Linux system calls that the name derives from.

Unix timestamp in milliseconds - a 13-digit number (as of 2024). For example, 1700000000000 is the same moment as above. JavaScript's Date.now() and new Date().getTime() return milliseconds. The extra precision is necessary for measuring elapsed time and ordering events that happen within the same second.

The easiest way to distinguish them: if the timestamp has 10 digits, it is in seconds; if it has 13 digits, it is in milliseconds. Timestamps from JavaScript are almost always in milliseconds; timestamps from most other languages are in seconds unless explicitly documented otherwise.

Common Uses of Unix Timestamps in Development

JWT expiration - JSON Web Tokens include exp (expiration) and iat (issued at) claims as Unix timestamps in seconds. When debugging authentication issues, converting these timestamps to human-readable dates reveals whether a token has expired.

API parameters - many APIs accept date ranges as Unix timestamps rather than formatted date strings, because timestamps are unambiguous (no timezone confusion) and easily compared with arithmetic.

Database queries - databases like PostgreSQL, MySQL, and MongoDB can store dates as Unix timestamps. Converting to human-readable format helps verify that stored dates are correct during debugging.

Log file analysis - many log formats include Unix timestamps. Converting them helps correlate events across different systems and identify when specific errors occurred.

Frequently Asked Questions

What is a Unix timestamp?
A Unix timestamp (also called epoch time, POSIX time, or Unix time) is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. It is the universal standard for representing time in computer systems, used in APIs, databases, log files, authentication tokens, and operating systems worldwide. The current Unix timestamp is displayed on the converter page and updates in real time.
How do I tell if a timestamp is in seconds or milliseconds?
Count the digits. A seconds timestamp is 10 digits as of 2024 (approximately 1,700,000,000 to 2,000,000,000). A milliseconds timestamp is 13 digits (1,700,000,000,000 to 2,000,000,000,000). A microseconds timestamp would be 16 digits. This converter auto-detects the format based on the number of digits. JavaScript's Date.now() always returns milliseconds. Most server-side languages (Python's time.time(), PHP's time(), Go's time.Unix()) return seconds by default.
Can I convert a specific date and time to a Unix timestamp?
Yes. Switch to the "Date to Timestamp" mode and enter a date and time using the date picker. The converter shows the corresponding Unix timestamp in both seconds and milliseconds. Note that the result depends on the timezone you are working in - if you enter "January 1, 2024 00:00:00" in local time, the timestamp will be different from the same date/time in UTC. The converter shows the timestamp for your local timezone.
What is the Y2038 problem?
On January 19, 2038, at 03:14:07 UTC, 32-bit Unix timestamps reach their maximum value (2,147,483,647) and will overflow (wrap around) to a negative number. This is the Unix equivalent of the Y2K problem. Systems still using 32-bit Unix timestamps after 2038 will experience date calculation errors. Modern 64-bit systems are not affected - 64-bit timestamps can represent dates far beyond any foreseeable need (approximately the year 292 billion).
Why do different systems show different dates for the same timestamp?
Unix timestamps are always in UTC (Coordinated Universal Time). When you convert a timestamp to a human-readable date, it must be interpreted in a timezone. The same timestamp represents January 1st at 2am in Paris, but January 1st at 1am in London, and December 31st at 8pm in New York. This converter shows the date in both UTC and your browser's local timezone to help you see the difference and pick the right interpretation for your context.