Timestamp Converter
Convert a Unix timestamp into something readable, or a date back into epoch. Seconds versus milliseconds is detected automatically, because that is the mistake everyone makes.
Runs entirely in your browser. Nothing you paste is uploaded.
About the Timestamp Converter
A Unix timestamp counts seconds since 1970-01-01T00:00:00Z. JavaScript's Date.now() returns milliseconds since that instant, which is why timestamps from JavaScript are 1000× larger than timestamps from most backends and why dates occasionally land in 1970 or in the year 55000.
A quick sanity check: a current timestamp in seconds is 10 digits, in milliseconds it is 13. The 10-digit era runs until 2286.
When storing time, prefer UTC everywhere and convert to local only for display. Storing local times without an offset is how you end up with an hour of duplicated or missing rows twice a year.
Frequently asked questions
Seconds or milliseconds — how do I tell?
Count the digits. Current timestamps are 10 digits in seconds and 13 in milliseconds. This tool detects and labels which one you pasted.
What is the year 2038 problem?
A signed 32-bit timestamp overflows on 19 January 2038. Any system still storing time in a 32-bit int will wrap to 1901. Use 64-bit integers and it is a non-issue.
What format should I use in APIs?
ISO 8601 with an explicit offset, like 2026-08-12T03:14:15Z. It is unambiguous, sorts lexicographically, and every language can parse it.