How do you use this tool?
- Paste a Unix timestamp (seconds or milliseconds) into the input field.
- The tool auto-detects whether it's in seconds or milliseconds based on magnitude.
- Read the converted date and time in UTC, your local timezone, and ISO 8601 format.
- To convert a date to a Unix timestamp, use the date picker and click 'To Epoch'.
- Copy the result to clipboard with one click.
What This Tool Does
This tool converts Unix epoch timestamps to human-readable dates and times — and converts dates back to Unix timestamps. It displays results in UTC, your browser’s local timezone, and ISO 8601 format simultaneously.
How It Works
The Unix epoch is defined as 00:00:00 Coordinated Universal Time (UTC) on Thursday, January 1, 1970. All Unix timestamps count forward from that moment:
| Timestamp (seconds) | Date (UTC) |
|---|---|
| 0 | 1970-01-01 00:00:00 |
| 86,400 | 1970-01-02 00:00:00 |
| 1,000,000,000 | 2001-09-08 21:46:40 |
| 1,700,000,000 | 2023-11-14 22:13:20 |
| 2,000,000,000 | 2033-05-18 03:33:20 |
The conversion is purely arithmetic. For millisecond timestamps, the tool divides by 1,000 first, then applies the same logic.
What Are Common Use Cases?
API response debugging. REST APIs often return dates as Unix timestamps in JSON. Seeing "expires_at": 1740000000 is meaningless at a glance — convert it to 2025-02-19 21:20:00 UTC to confirm the expiry is as expected.
Log file analysis. Web server and application logs frequently store timestamps as epoch values for compact storage and easy sorting. Convert specific log entries to confirm when an error or event occurred in your local time.
Database timestamps. PostgreSQL, MySQL, and SQLite can store timestamps as integer epoch values. When debugging a query result, paste the value here to see the human-readable date without writing a conversion query.
JWT token inspection. JSON Web Tokens include iat (issued at) and exp (expires) claims as Unix timestamps. Converting the exp value tells you immediately whether a token is still valid.
Cookie expiration. HTTP Set-Cookie headers use Max-Age in seconds from now, or an explicit Expires date. Tools that return the raw epoch value for Expires can be decoded here.
JavaScript Date debugging. JavaScript’s Date object operates in milliseconds. When console.log(Date.now()) returns 1714000000000, this tool converts it instantly without mental division.
What Formats Are Supported?
The tool outputs the timestamp in multiple formats:
| Format | Example |
|---|---|
| UTC | 2025-04-26 14:30:00 UTC |
| Local time | 2025-04-26 10:30:00 EDT (UTC−4) |
| ISO 8601 | 2025-04-26T14:30:00.000Z |
| RFC 2822 | Sat, 26 Apr 2025 14:30:00 +0000 |
| Day of week | Saturday |
Frequently Asked Questions
What happens with negative Unix timestamps? Negative values represent dates before January 1, 1970. For example, -86,400 = December 31, 1969, 00:00:00 UTC. Most systems support negative timestamps, though some older APIs may not.
Why do some APIs use milliseconds instead of seconds?
JavaScript popularized millisecond-precision timestamps because Date.now() returns milliseconds natively. APIs designed for JavaScript clients (REST, GraphQL, web hooks) often adopt milliseconds for consistency with the client-side environment.
How precise is this conversion? To millisecond precision — the maximum resolution of standard Unix timestamps. Sub-millisecond precision (microseconds, nanoseconds) requires specialized high-resolution timers not covered by the standard epoch format.
Last updated: