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Free Online Unix Timestamp Converter

Convert Unix timestamps to readable dates and dates to Unix timestamps. Auto-detects seconds vs milliseconds. Supports 8 timezones, ISO 8601, relative time.

LIVE Current Unix Timestamp

Unix Timestamp → Human-Readable Date

Date → Unix Timestamp

All conversions happen locally in your browser. No data is ever sent to our servers.

What is a Unix Timestamp?

A Unix timestamp (also called epoch time or POSIX time) is the number of seconds elapsed since 00:00:00 UTC on 1 January 1970 — the Unix epoch. This zero-point was chosen because it preceded widespread Unix adoption, making it a neutral reference for all Unix systems. Timestamps are timezone-independent integers, which makes them perfect for databases, APIs, log files, and JWT tokens where a single universal reference point is essential.

Unix Timestamp: Seconds vs Milliseconds

The most common source of confusion is whether a timestamp is in seconds (10 digits) or milliseconds (13 digits). The rule: if the value exceeds 10¹² it is almost certainly milliseconds.

Seconds (10 digits) 10 digits

Used by PHP time(), Python time.time(), Unix shell date +%s, and most SQL databases. Example: 1710508200

1710508200
Milliseconds (13 digits) 13 digits

Used by JavaScript Date.now(), Java System.currentTimeMillis(), Node.js, and most browser APIs. Example: 1710508200000

1710508200000

Common Timestamp Use Cases

Why developers prefer Unix timestamps over human-readable date strings:

JWT iat & exp Claims

JSON Web Tokens use Unix timestamps in seconds for the "issued at" (iat) and "expiration" (exp) claims. Timezone-independent and trivially comparable.

Database Chronological Sorting

An integer timestamp column sorts faster than a datetime string and is timezone-neutral, eliminating ambiguity when records come from multiple geographic locations.

Log File Analysis & Event Correlation

Server logs, distributed tracing (OpenTelemetry), and analytics pipelines use millisecond timestamps to correlate events across services with sub-second precision.

Cache Expiration & TTL

Cache systems (Redis, Varnish, CDNs) and API responses use Unix timestamps for Cache-Control max-age, created_at, and updated_at fields.

Frequently Asked Questions

The Unix epoch is midnight UTC on 1 January 1970. This date was chosen by the early Unix developers at Bell Labs as a practical starting point that preceded widespread adoption of Unix. It has no mathematical significance — it simply needed to be a recent date before any existing Unix systems were deployed. The resulting integer counter is small enough to fit in a 32-bit integer (though the Year 2038 problem arises from signed 32-bit overflow).

Simple rule: if the value has more than 11 digits (greater than approximately 10¹¹), it is almost certainly in milliseconds. A current Unix timestamp in seconds is 10 digits (e.g. 1710508200). The same moment in milliseconds is 1710508200000 (13 digits). This converter auto-detects the unit when you paste a timestamp.

Yes. The Unix → Date direction uses the Intl.DateTimeFormat API to render the UTC moment in the selected IANA timezone. The Date → Unix direction performs the reverse: it interprets your datetime-local input as local time in the chosen timezone and computes the corresponding UTC Unix timestamp. ISO 8601 output always shows UTC (Z suffix) regardless of the selected timezone.

ISO 8601 is the international standard for representing dates and times, e.g. 2024-03-15T14:30:00.000Z. The Z suffix denotes UTC. Use ISO 8601 in REST APIs, JSON payloads, and HTML datetime attributes — it is unambiguous across locales and directly parseable by JavaScript (new Date("2024-03-15T14:30:00Z")), Python (datetime.fromisoformat()), and most modern languages.