Timestamp Converter
Convert Unix timestamps and date strings to ISO, UTC, local, and relative time.
Enter a Unix timestamp or date string to see every format.
What is Timestamp Converter?
A Unix timestamp is the number of seconds (or milliseconds) that have elapsed since the Unix epoch of 1970-01-01T00:00:00Z, used across operating systems, databases, and logs as a timezone-independent way to mark an instant. This tool converts between that number and human-readable forms including ISO 8601, UTC, your browser's local time, and a relative description such as 3 hours ago. It auto-detects whether a numeric input is in seconds (10 digits today) or milliseconds (13 digits), and supports negative values for dates before 1970. Conversion happens entirely client-side, using your browser's own timezone for the local rendering.
How to Use Timestamp Converter
- Type a Unix timestamp (in seconds or milliseconds) or a date string into the input.
- The tool auto-detects which one you entered and shows every common format at once.
- Click "Use current time" to fill in right now as a starting point.
- Copy any of the output rows — ISO 8601, UTC, your local time, or the raw Unix values.
Examples
Unix seconds
Input: 1700000000
Output: 2023-11-14T22:13:20.000Z
Unix milliseconds
Input: 1700000000000
Output: 2023-11-14T22:13:20.000Z
ISO date string
Input: 2026-07-25T10:00:00Z
Output: 1784973600 (Unix seconds)
Common Mistakes
- Mixing up seconds and milliseconds — passing a seconds-based timestamp to a library (like JavaScript's `new Date()`) that expects milliseconds produces a date in 1970, not an error.
- Assuming a timestamp is already in your local timezone when it's actually UTC (or vice versa), leading to off-by-several-hours bugs.
- Forgetting that Unix time is timezone-agnostic — it's the same number everywhere on Earth; only its human-readable rendering changes by timezone.
Why Use This Tool
- Single input auto-detects Unix seconds, Unix milliseconds, or a date string — no mode switch needed.
- Shows ISO 8601, UTC, local time, relative time, and both Unix formats side by side.
- Supports negative (pre-1970) timestamps.
- Runs entirely client-side using your browser's own timezone — nothing is sent to a server.