Unix Timestamp Converter — Free Online Tool

A Unix timestamp converter translates between Unix epoch timestamps and human-readable dates. Developers use it to debug log timestamps, convert API date fields, and verify time calculations in applications that store dates as seconds or milliseconds since January 1, 1970.

Features

• Auto-detection: Automatically determines if input is a timestamp or a date string.
• Seconds and milliseconds: Handles both second-precision and millisecond-precision Unix timestamps.
• Multiple date formats: Parses ISO 8601, RFC 2822, and common date string formats.
• No signup or account required: Use instantly — no registration, email, or login needed.

Frequently Asked Questions

What is a Unix timestamp?

The number of seconds (or milliseconds) elapsed since January 1, 1970 00:00:00 UTC — also called the Unix epoch.

How do I tell seconds from milliseconds?

Timestamps around 1.7 billion are in seconds (current era). Timestamps around 1.7 trillion are in milliseconds.

Does it handle negative timestamps?

Yes. Negative timestamps represent dates before January 1, 1970.

Does it handle millisecond timestamps?

Yes. The tool auto-detects whether your input is in seconds or milliseconds and converts accordingly.

What timezone does it use?

The tool displays results in both UTC and your local browser timezone so you can compare directly.

Is this tool free?

Yes, this tool is completely free with no usage limits, no ads, and no account required.

Does it work offline?

Yes. Once the page loads, all processing happens locally in your browser — no internet connection needed.

Is my data safe with this tool?

Absolutely. Your data never leaves your browser. Everything is processed client-side with zero server uploads.

What happened to smalldev.tools?

smalldev.tools is no longer available. Prism by SWEDevTools offers the same developer tools and more, with offline support, pipeline chaining, and completely free usage — no signup required.