Unix Timestamp Converter
Turn a Unix timestamp into a readable date, or a date into a timestamp: seconds, milliseconds, microseconds and nanoseconds with auto-detection, UTC plus local and 11 extra timezones, relative time, and batch conversion, all in your browser.
Your conversion will appear here. Enter a timestamp or a date and press Convert.
Privacy: conversion runs locally in your browser. Nothing you enter is uploaded or logged.
How this calculator works
A Unix timestamp is a single integer counting the seconds since January 1, 1970, 00:00:00 UTC, the moment called the Unix epoch. APIs, databases, log files and JWT tokens all store time this way because one number is timezone-free, sortable and trivially comparable, but humans cannot read it at a glance. This tool converts in both directions, entirely in your browser. Paste a timestamp and get its date; enter a date and get its timestamp.
Timestamps come in four units and mixing them up is the classic bug: 10 digits means seconds, the format most APIs and databases use; 13 digits means milliseconds, what JavaScript Date.now() returns; 16 digits means microseconds, common in high-precision logs; 19 digits means nanoseconds, used by Go and system clocks. A millisecond value read as seconds lands in the year 56,189, which is how you spot the mistake. Leave the unit on Auto-detect and the tool reads the digit count for you. Worked example: 1700000000 is 10 digits, so seconds, and converts to Tuesday, November 14, 2023, 22:13:20 UTC, ISO 8601 2023-11-14T22:13:20.000Z; the same moment in milliseconds is 1700000000000.
Three features save real debugging time. First, timezones: the same instant is shown in UTC, in your local time, and in any of 11 extra zones from New York to Sydney, because a log timestamp that looks wrong is often just a zone mismatch, not a wrong value. Second, relative time: "3 hours ago" or "in 2 days" answers the question behind most conversions, whether a token expired or a scheduled job already ran. Third, batch mode: paste a whole column of timestamps from a log file, one per line, and get every date back as a table you can copy as CSV, instead of converting values one by one. Nothing you enter leaves your machine in any mode, which is why the tool is safe for production log excerpts and API payloads.