Unix Timestamp to Date Converter Online — Free
Runs 100% in your browser — your files never leave your device.
Timestamps like 1700000000 are everywhere — APIs, log files, databases — and doing the math on them in your head is hopeless. Paste a Unix timestamp (seconds or milliseconds, auto-detected) or any date string and get every useful form at once: Unix seconds, milliseconds, ISO 8601, RFC 2822, and your local time. One click copies any of them.
How it works
- 1
Paste a timestamp or date
Plain numbers are read as Unix time — under 13 digits means seconds, 13+ means milliseconds.
- 2
Read every format at once
Unix seconds, milliseconds, ISO 8601, RFC 2822, and your local time.
- 3
Copy what you need
Each format has its own copy button — or press Now to stamp the current time.
About this tool
What the converter decodes
Paste a Unix timestamp — seconds or milliseconds, auto-detected — and the tool shows the exact moment as ISO 8601, RFC-style, and human-readable local time. Paste a readable date and get the timestamp back. Every format developers trade timestamps in, one tool.
The seconds-versus-milliseconds trap
Two conventions divide the timestamp world: seconds since 1970 (Unix classic) and milliseconds (JavaScript, Java). A 10-digit number is seconds; a 13-digit number is milliseconds — the auto-detection reads the length and converts accordingly, and the misread explains most "date in 1970" bugs.
Timestamps know no timezone
A Unix timestamp is the same instant everywhere — the timezone enters only when humans read it. The converter shows the moment in your browser's local time and in UTC, so you can confirm whether the timestamp or the display was wrong.
Frequently asked questions
How do I tell seconds from milliseconds?
Count digits: 10 digits is seconds (until the year 2286), 13 digits is milliseconds. The tool auto-detects by length and converts to real time either way.
What is the Unix epoch?
Midnight UTC on January 1, 1970 — the zero point every Unix timestamp counts from. Negative timestamps predate it.
Why does my timestamp show a different time than expected?
The timestamp is exact; the display applies your browser's timezone. Compare against the UTC output to see whether the value or the expectation was off.