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Unix Timestamp Converter

Convert between Unix timestamps and human dates with live ticking clock.

Unix timestamp (seconds or ms)

Date (any parseable string)

Convert Unix timestamps to human-readable dates (and back)

A Unix timestamp is the number of seconds since January 1, 1970 UTC. JavaScript usually deals in milliseconds (since-epoch × 1000), and most backend APIs return seconds. This converter accepts either, auto-detects the unit, and shows the result in eight common formats — local time, UTC, ISO 8601, date-only, time-only, Unix seconds, Unix milliseconds, and a human relative phrase ("3 hours ago").

Seconds vs milliseconds

If your timestamp has 10 digits, it's seconds. 13 digits is milliseconds. The tool auto-detects: anything below 10¹² is treated as seconds and multiplied by 1000.

Use cases

Decoding the iat, exp, or nbf claims in a JWT.
Reading a Stripe webhook timestamp.
Translating a database created_at column into your local timezone.
Building a "last seen" relative-time string for a UI.

Timezones

Unix timestamps are always UTC by definition — they have no timezone. The "Local" output uses your browser's timezone; the "UTC" output is the canonical one. When in doubt, share UTC strings.

Related tools

FAQ

Are timestamps in seconds or milliseconds?

JavaScript and many web APIs use milliseconds. Most backend systems and Unix tools use seconds. This tool auto-detects based on magnitude.

Does it handle negative timestamps (pre-1970)?

Yes — Date supports negative milliseconds back to about year -271,000.

Why is the local time different from UTC?

Your browser converts to your operating system's timezone for display. Unix timestamps themselves are timezone-less.