Unix Timestamp Converter works in both directions: paste a Unix timestamp (seconds or milliseconds — auto-detected) and see the UTC date, local timezone date, and ISO 8601 string. Or pick a date and time to get its Unix seconds and milliseconds. A 'Now' button fills the current moment.
If the timestamp has 13 or more digits it is treated as milliseconds; otherwise as seconds. This correctly handles all timestamps from 1970 through the year 2286.
The local timezone display uses your browser's system timezone, reflecting whatever timezone is configured on your device.
A Unix timestamp (or epoch time) is the number of seconds (or milliseconds) that have elapsed since January 1, 1970, 00:00:00 UTC. It's used widely in databases, APIs, and log files.
10-digit timestamps are seconds-based (the original Unix standard), while 13-digit timestamps are milliseconds-based, common in JavaScript (Date.now()) and many web APIs. Both are common — the tool auto-detects which one you've pasted.
Negative Unix timestamps represent dates before January 1, 1970, and are technically valid, but this tool is optimized for typical positive timestamps used in modern applications.
ISO 8601 is a standardized format like 2026-06-10T14:30:00.000Z, commonly used in JSON APIs, logs, and databases because it's unambiguous and sortable as a string.
Yes — use the date picker and leave the time at its default (usually midnight) to get the timestamp for the start of that day in your local timezone.
