Convert Unix epoch timestamps (seconds and milliseconds) to human-readable ISO 8601, UTC, and local date strings with real-time relative time calculation.
All formatting, parsing, decoding, and validation executes entirely within your browser using modern Web APIs and JavaScript. Your tokens, JSON payloads, regex inputs, and queries never leave your computer.
Unix time (also known as POSIX time or epoch time) measures time as the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970. It is the universal standard for database timestamps, JWT expiration claims (exp, iat), cache headers, and distributed server logs.
DevRef's Unix Timestamp Converter automatically detects whether your input is in seconds (10 digits) or milliseconds (13 digits), instantly converting between epoch numbers and RFC 3339 / ISO 8601 formats. All date parsing and timezone calculations execute client-side in your browser using the native ECMAScript Intl and Date APIs.
Unix seconds are 10 digits long (e.g. 1719187200), commonly used in Unix systems, Python, and JWT claims. Milliseconds are 13 digits long (e.g. 1719187200000), standard in JavaScript Date.now() and Java timestamps.
On January 19, 2038, 32-bit signed integers will overflow. Modern 64-bit systems and JavaScript numbers (which support safe integers up to 2^53 - 1) handle timestamps far into the future without issue.
Yes. All time conversions run locally using your browser's JavaScript Date and Intl engines. No network requests are required.
Understand how exp and iat numeric dates work in JWT authentication tokens.
Schedule automated background jobs and recurring tasks with cron expressions.
Inspect decoded JSON Web Tokens, expiration dates, and custom authentication claims.