The timestamp converter turns machine timestamps into human-readable dates and back. Paste Unix seconds, Unix milliseconds, a 16-digit microsecond value, an ISO 8601 string or the literal word "now", and it tells you the exact instant in UTC, in your local time zone, and as a relative phrase like "in 3 days" or "2 hours ago".
Everything is computed in your browser — no request leaves your machine. That means you can safely convert timestamps pulled from production logs, database rows or webhook payloads without anything being uploaded. It is free, needs no account, and works offline.
It handles many lines at once: put one timestamp per line and you get back a JSON array with a small object for each, containing the input, Unix seconds, Unix milliseconds, the ISO string, a UTC string, your local string and the relative time. It is the fastest way to make sense of a column of epoch numbers.
The converter reads the magnitude of a numeric line to pick the unit: values with 13 or more digits (or magnitude at or above 1e12) are treated as milliseconds, 16-digit values as microseconds, and everything else as Unix seconds. So 1751961600 is read as seconds and 1751961600000 as milliseconds — no dropdown needed.
Any string the browser's Date can parse works, including ISO 8601 with or without a timezone offset (2026-08-01T00:00:00Z). Type the literal word "now" on a line to convert the current moment — handy for grabbing the current epoch in seconds and milliseconds at once.
Each result shows the instant three ways: a UTC string, a string in your machine's local time zone, and a relative phrase built with Intl.RelativeTimeFormat ("in 3 weeks", "5 minutes ago"). That covers debugging across time zones and quickly judging how old a record is.
A single timestamp returns one JSON object; multiple non-empty lines return a JSON array, one entry per line. If any line is not a valid timestamp the tool stops and names the offending line number so you can fix it, rather than silently skipping it.
Paste the epoch value on its own line and the converter returns the ISO 8601 date, a UTC string and your local time. It auto-detects whether the number is in seconds or milliseconds from its size, so you do not need to specify the unit.
Unix seconds count whole seconds since 1970-01-01 UTC (10 digits for current dates); milliseconds count thousandths of a second (13 digits). JavaScript's Date uses milliseconds, while many databases and APIs store seconds. The converter shows both so you never have to multiply or divide by 1000 by hand.
Yes. Any ISO 8601 string the browser can parse works, including a trailing Z or a numeric offset like +02:00. The output always includes an unambiguous UTC string plus your local-time rendering so cross-zone timestamps are easy to line up.
Put one timestamp per line. Each line becomes an object in a JSON array with its Unix seconds, milliseconds, ISO, UTC, local and relative time. Mixing formats across lines is fine — seconds, milliseconds, ISO and "now" can all appear together.
No. All parsing and formatting runs in your browser with the built-in Date and Intl APIs. Nothing is sent to a server, so timestamps from logs or production data stay private, and the tool keeps working offline.