Unix Timestamp Converter
Convert between Unix timestamps (epoch time) and human-readable dates in both directions. Handles seconds and milliseconds, in your local time and UTC.
Current Unix time:
Timestamp → Date
Date → Timestamp
What is a Unix timestamp?
A Unix timestamp (also called epoch time) is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. It's a compact, timezone-free way for computers to store a moment in time. Many systems use milliseconds instead (multiply by 1000). This tool auto-detects which you've entered.
Why programs use epoch time
Storing a moment as a single number sidesteps a mountain of complexity: no timezones, no date formats, no ambiguity about "03/04" meaning March 4th or April 3rd. Two timestamps are trivial to compare or subtract to get a duration. That's why databases, logs, APIs, and file systems lean on epoch time internally, converting to human-readable dates only when showing them to people.
Seconds vs. milliseconds
Unix time is classically counted in seconds (a 10-digit number today), but JavaScript and many APIs use milliseconds (13 digits). Mixing them up is a common bug — a value read as seconds instead of milliseconds lands 50,000 years in the future. This converter checks the digit count and interprets it correctly either way.
UTC vs. local time
A timestamp itself has no timezone — it's an absolute instant. When you convert it to a readable date, the result shows in a timezone. This tool gives you both your local time and UTC, plus the ISO 8601 string, so you can see exactly what a value means everywhere. Everything is computed in your browser with no network calls.
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Frequently asked questions
Does this support milliseconds?
Yes. If your number has 13 digits it's treated as milliseconds; 10 digits is treated as seconds. The converter detects this automatically.
Is the conversion done privately?
Yes — it runs entirely in your browser using the JavaScript Date object. Nothing is uploaded.