How It Works

This tool converts between human-readable date/time values and Unix timestamps — entirely inside your browser. No data is sent to a server.

What is a Unix Timestamp?

A Unix timestamp (also called an epoch timestamp) is the number of seconds — or milliseconds — that have elapsed since 00:00:00 UTC on 1 January 1970, known as the Unix epoch. It is a timezone-independent, language-agnostic way to represent a point in time and is widely used in databases, APIs, log files, and JWT tokens.

Implementation Details

All date arithmetic uses JavaScript’s built-in Date object — no third-party library is needed.

• Date/Time → Epoch: The <input type="datetime-local"> value is parsed with new Date(val). Date.getTime() returns the Unix timestamp in milliseconds; dividing by 1000 and flooring gives seconds. The input is pre-filled with the current local time for convenience.
• Epoch → Date/Time: The raw number is checked against a threshold of 10¹⁰ (approximately November 2286 in seconds). Values above this threshold are treated as milliseconds; values below are multiplied by 1000 and treated as seconds. The resulting Date object is then formatted as UTC, local, and ISO 8601 strings using the browser’s native formatting methods.
• Live clock: A setInterval callback fires every second, calling new Date() and updating the current seconds, milliseconds, and UTC string in real time.

Output Formats

Privacy

All conversions run locally in your browser tab. No timestamps or dates are transmitted anywhere.