Unix Timestamp Converter
Convert Unix timestamps to ISO 8601, local time, and relative time — and back again.
100% in your browser — files never leave your device
Current time
1785274550
1785274550125
2026-07-28T21:35:50.125Z
From timestamp
From date
Timezone viewer
Shows the currently entered timestamp or date (or now if neither is set) in the selected timezone.
How timestamp conversion works
The tool has to guess whether a number you paste is Unix seconds or milliseconds, since both are common. It uses a simple threshold: absolute values at or above 10^12 are treated as milliseconds, everything below as seconds. That boundary correctly covers every date from 1970 through the year 33658, so it won't misfire on any realistic timestamp.
The timezone viewer uses Intl.DateTimeFormat with your browser's built-in IANA timezone database — the same data your operating system uses — so the list of zones and their current UTC offsets (including DST) stay accurate without the tool bundling its own timezone data.
Free-text date parsing in the "From date" field goes through the browser's native Date constructor, which reliably handles ISO 8601 (2024-06-15T12:00:00Z) but parses locale-ambiguous formats like 06/15/2024 inconsistently across browsers. Stick to ISO 8601 if the result needs to be trustworthy.
Frequently asked questions
Is any data sent to a server?
No. All conversions happen locally in your browser using the JavaScript Date API. Nothing is transmitted anywhere.
How does the tool tell seconds from milliseconds?
If the absolute value of the number is 1,000,000,000,000 (10^12) or greater it is treated as milliseconds; otherwise as Unix seconds. This threshold correctly covers all dates from 1970 to the year 33658.
What date string formats does "From date" accept?
Any format the browser's Date constructor can parse — most reliably ISO 8601 (e.g., 2024-06-15T12:00:00Z, 2024-06-15). Ambiguous locale formats like 06/15/2024 may parse inconsistently across browsers.