Convert Unix timestamps to readable dates and convert dates back to Unix timestamps with this free online tool. It supports both seconds and milliseconds precision, automatically detecting which format you are using. This makes it ideal for developers working with REST APIs, databases, system logs, JWT tokens, and cookie expiration dates. Enter a numeric timestamp or an ISO date string and get the conversion instantly. Everything runs in your browser with no data sent anywhere.
Enter your values to see the result.
Enter your values to see the result.
1700000000 → Tue, 14 Nov 2023 22:13:20 GMT
A common test timestamp in seconds.
0 → Thu, 01 Jan 1970 00:00:00 GMT
The Unix epoch — the starting point of Unix time.
2024-01-15T12:00:00Z → 1705320000
Converting a date back to its Unix timestamp.
Unix timestamps are everywhere in software development. APIs return them, databases store them, and system logs use them. But a number like 1700000000 is not human-readable. When debugging, analyzing logs, or building features that involve dates, you frequently need to translate between the machine representation and something you can read.
This converter provides both directions: timestamp to date and date to timestamp.
Unix time counts the seconds since January 1, 1970, 00:00:00 UTC. This single number provides a universal, timezone-independent way to represent any moment in time. It is used by operating systems, programming languages, databases, and network protocols.
The epoch was chosen arbitrarily but has become the de facto standard for computer time representation. Every modern operating system can convert between Unix time and calendar dates.
Most Unix systems, C libraries, and REST APIs use seconds. JavaScript, Java, and some databases use milliseconds. The difference matters — a seconds timestamp is 10 digits (for current dates), while a milliseconds timestamp is 13 digits.
This tool auto-detects the precision: values above one trillion are treated as milliseconds. This covers all realistic current timestamps correctly.
Timestamp to date: The tool takes the numeric value, adjusts for seconds vs milliseconds, creates a Date object, and formats it as a UTC string using the standard RFC 2822 format.
Date to timestamp: The tool parses the input date string, creates a Date object, and divides the internal millisecond value by 1000 to get seconds. The result is always in seconds since the epoch.
API debugging — Convert timestamps returned by REST APIs to readable dates when inspecting responses.
Database queries — Translate stored timestamps when examining records in admin tools or logs.
Log analysis — Convert epoch timestamps in system logs to human-readable dates for incident investigation.
Cross-platform development — Convert between JavaScript millisecond timestamps and Unix second timestamps when integrating systems.
Cookie and token expiration — Check when a JWT token or session cookie expires by converting its exp claim.
All conversions happen in your browser using standard JavaScript Date operations. No data is sent to any server. Results are accurate for all valid timestamps within the supported range.
A Unix timestamp is the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, known as the Unix epoch. It is a single number that represents a specific moment in time, independent of time zones or calendar systems.
This tool auto-detects the precision. Timestamps greater than 10^12 (one trillion) are treated as milliseconds; smaller values are treated as seconds. As a rule of thumb, 10-digit numbers are seconds and 13-digit numbers are milliseconds.
JavaScript's Date object uses milliseconds since the epoch, while most Unix systems and APIs use seconds. When working across languages and platforms, you often need to convert between the two. This tool handles both automatically.
Use ISO 8601 format, such as 2024-01-15T12:00:00Z. The Z suffix indicates UTC. You can also use formats like 2024-01-15 or January 15, 2024, but ISO format is the most unambiguous.
No, all timestamp conversions happen entirely in your browser using standard JavaScript Date operations. No timestamps, dates, or any other data are transmitted to any server, stored in any database, or logged anywhere. The tool runs completely locally on your device and produces results instantly with no network requests at all.
Last updated on 2026-09-26 · Written by UtiliaTools