liminfoUnix Timestamp
Free web tool: Unix Timestamp
17719797962/25/2026, 9:36:36 AM
About Unix Timestamp
The Unix Timestamp Converter is a free online tool for converting between Unix timestamps (epoch time) and human-readable dates. Whether you are analyzing server logs, debugging API responses, working with database records, or scheduling events in distributed systems, this tool lets you instantly translate numeric timestamps into formatted dates and vice versa.
Unix timestamps represent the number of seconds (or milliseconds) elapsed since January 1, 1970 00:00:00 UTC, known as the Unix epoch. This format is the universal standard for recording time in programming, databases, and system logs. Our converter supports both seconds and milliseconds precision, displays results in local time, UTC, and ISO 8601 format, and shows a live-updating current timestamp for quick reference.
All conversion happens entirely in your browser using JavaScript Date APIs. No data is sent to any server, making this tool safe for working with timestamps from production logs or sensitive systems. The interface is optimized for developers who need to quickly verify timestamps during debugging sessions.
Key Features
- Bidirectional conversion: Unix timestamp to human-readable date and date string to Unix timestamp
- Auto-detection of seconds vs. milliseconds timestamps (values above 1 trillion are treated as milliseconds)
- Live current Unix timestamp counter that updates every second
- Output in three formats simultaneously: local time, UTC, and ISO 8601
- One-click copy for the current timestamp, conversion results, and individual values
- Support for any valid date string input including ISO 8601, RFC 2822, and natural date formats
- Millisecond-precision output for both seconds and milliseconds representations
- Instant error feedback for invalid timestamps or malformed date strings
Frequently Asked Questions
What is a Unix timestamp?
A Unix timestamp (also called epoch time or POSIX time) is a system for tracking time as a single number: the count of seconds that have elapsed since January 1, 1970 00:00:00 UTC. For example, the timestamp 1700000000 represents November 14, 2023 at 22:13:20 UTC. This format is used universally in programming, databases, APIs, and system logs because it is timezone-independent and easy to compare mathematically.
What is the Unix epoch and why does it start from 1970?
The Unix epoch is the reference point for Unix time: January 1, 1970 at 00:00:00 UTC. This date was chosen by the early Unix engineers at Bell Labs because Unix was being developed around that time, and they needed a recent, round date as a starting point. The original Unix time was stored as a 32-bit signed integer counting seconds from this epoch.
What is the difference between seconds and milliseconds timestamps?
A seconds-based Unix timestamp is typically a 10-digit number (e.g., 1700000000), while a milliseconds timestamp is 13 digits (e.g., 1700000000000). JavaScript Date.now() returns milliseconds, while many Unix systems and APIs use seconds. This tool auto-detects which format you enter: values greater than 1 trillion are treated as milliseconds and divided by 1000 for conversion.
What is the Y2038 problem?
The Year 2038 problem (also called the Unix Millennium Bug) occurs because many systems store Unix time as a 32-bit signed integer, which can represent a maximum value of 2,147,483,647. This corresponds to January 19, 2038 at 03:14:07 UTC. After this moment, the counter overflows to a negative number, potentially causing dates to wrap around to December 13, 1901. Modern systems are migrating to 64-bit integers, which extend the range to approximately 292 billion years.
How do I convert a Unix timestamp in JavaScript?
In JavaScript, use new Date(timestamp * 1000) to convert a seconds-based timestamp to a Date object (multiply by 1000 because JavaScript Date expects milliseconds). To get the current timestamp in seconds, use Math.floor(Date.now() / 1000). For formatting, use toISOString(), toLocaleString(), or toUTCString() on the Date object.
What is ISO 8601 format and how does it relate to timestamps?
ISO 8601 is the international standard for date and time representation, using the format YYYY-MM-DDTHH:mm:ss.sssZ (e.g., 2023-11-14T22:13:20.000Z). The trailing Z indicates UTC time. This format is widely used in APIs, JSON data, and logging systems because it is unambiguous, sortable as a string, and timezone-aware. This tool outputs ISO 8601 alongside local and UTC formats for every conversion.
Can I use negative Unix timestamps?
Yes, negative Unix timestamps represent dates before the epoch (January 1, 1970). For example, -86400 represents December 31, 1969. JavaScript Date supports negative timestamps, so this tool can convert dates as far back as the JavaScript Date range allows (approximately 270,000 years before the epoch). This is useful for historical date calculations.
Why do APIs and databases use Unix timestamps instead of formatted dates?
Unix timestamps offer several advantages for machines: they are timezone-neutral (always UTC-based), occupy fixed storage space (a single integer), can be compared and sorted with simple arithmetic, and avoid ambiguity from regional date formatting differences (MM/DD vs DD/MM). They are also easy to transmit in JSON, query parameters, and binary protocols without encoding issues.