How do I tell if a timestamp is in seconds or milliseconds?

A current-day timestamp in seconds is a 10-digit number, while the same moment in milliseconds is a 13-digit number -- this tool detects and converts either format automatically.

Why does the same timestamp show a different local time for me than someone else?

A Unix timestamp represents a single fixed instant, but "local time" is calculated using your device's timezone setting, so the same timestamp displays a different clock time depending on where the viewer is.

developer Client-Side Only

Unix Timestamp Converter

Convert Unix epoch timestamps (seconds & milliseconds) to human dates (UTC & Local) and vice versa.

Unix Timestamp (seconds/ms) or ISO Date

⚠️ Invalid timestamp or date format.

Zero-Leakage Local Processing

All text formatting, JSON/JWT parsing, cryptographic hashing, and image compression execute entirely inside your browser. No private data is ever sent to Burnjet servers.

Quick Reference & Instructions

Simple steps, pro tips, and execution details

Paste or Enter Input

Paste your raw JSON, code snippet, tokens, or values into the input panel.

Select Options & Modes

Choose formatting options, indentation spaces, or target conversion standards.

Copy or Download Output

One-click copy to clipboard or download the formatted file ready for production.

How It Works

Converts timestamp integers to ISO strings, UTC dates, and relative time offsets.

Frequently Asked Questions

Common questions about calculations, assumptions, and edge cases.

It's the number of seconds (or milliseconds) that have elapsed since midnight UTC on January 1, 1970 (the "Unix epoch") -- a compact, timezone-independent way computers represent a point in time.

In-Depth Guides & Tutorials

Explore all guides →

7 min read•development

Unix Timestamp Explained: Convert Unix Time to Date and Back

Understand what Unix Epoch time is, the critical difference between seconds and milliseconds, and how to convert timestamps to UTC and ISO 8601 strings.

Read Tutorial

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