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

Timestamps with 13 or more digits are almost always in milliseconds. Timestamps with 10 digits are in seconds. This tool auto-detects which one you have by checking whether the absolute value is 1 trillion or greater.

Why do some systems use milliseconds instead of seconds?

Languages like JavaScript use milliseconds because modern applications need sub-second precision for animations, logging, and performance timing. Unix-level tools such as shell scripts and most databases traditionally use seconds.

Utility

Epoch / Timestamp Converter

Instantly convert a Unix epoch to a readable date or a date back to epoch. Auto-detects seconds vs milliseconds.

Runs locally
Works offline
No sign-up

Epoch converter

Unix time to readable dates

Epoch to Date

Unix timestamp (seconds or milliseconds)

Date to Epoch

Date and time (local)

All conversions run locally. Nothing is uploaded.

About this tool

This tool converts in both directions: paste any Unix timestamp and get the ISO (UTC) string, your local date and time, and a relative label like "3 hours ago". Or pick a date with the date picker and get the matching epoch in both seconds and milliseconds.

Everything runs locally in your browser. Nothing is sent to a server.

What is epoch time?

Unix epoch: the number of seconds since January 1, 1970, 00:00:00 UTC. It is timezone-independent and unambiguous.
Milliseconds: JavaScript's Date.now() and many APIs return milliseconds. A 13-digit number is a strong signal you have milliseconds.
ISO 8601: the standard text format for dates, e.g. 2023-11-14T22:13:20.000Z. The trailing Z means UTC.

Tips

Paste a 13-digit timestamp directly. The tool detects it as milliseconds and converts automatically.
Use Now to capture the current moment for logging or debugging.
Copy the epoch seconds with the Copy button and paste it into a database query or API request.
The relative label updates against the current time when you type, so "X minutes ago" is always accurate.

About the Epoch Converter

Unix timestamps are the lingua franca of backend systems. Every Android log line, every API response, every SQLite row that stores a date uses one. Reading them by eye is tedious: 1700000000 does not tell you it is November 2023. This tool translates that number into something you can actually reason about.

Seconds vs milliseconds

The original Unix timestamp counts whole seconds. But JavaScript, Android's SystemClock.elapsedRealtimeNanos(), and most modern REST APIs count in milliseconds for sub-second resolution. A 10-digit number is almost certainly seconds; a 13-digit number is almost certainly milliseconds. This converter checks the magnitude automatically and adjusts, so you never have to think about it.

ISO 8601 and UTC

The output ISO string is always in UTC, marked with a trailing Z. That is the safest form to store or share, because it has no ambiguity around daylight-saving transitions or regional offsets. The local-time row converts to your browser's configured timezone, which is useful for a quick sanity check but should not be stored in a database.

Converting a date back to epoch

Pick a date and time in the second section. The converter returns the epoch in both seconds and milliseconds, with a copy button for each. This is useful when you need to query a time range in a database, build a test fixture, or craft a signed URL with an expiry.

Frequently asked questions

What is a Unix epoch timestamp?

A count of seconds (or milliseconds) since January 1, 1970 at 00:00:00 UTC. It is the standard way to store and transmit moments in time without timezone confusion.

How do I tell if my timestamp is seconds or milliseconds?

Count the digits. A 10-digit number (around 1.7 billion) is seconds. A 13-digit number (around 1.7 trillion) is milliseconds. This tool auto-detects it for you.

Why does the ISO output end in Z?

The Z is shorthand for UTC (Coordinated Universal Time). It means the time has no timezone offset applied. Always store and share dates in UTC to avoid daylight-saving bugs.

Can I use this tool for Android logcat timestamps?

Yes. Android logs often include a Unix timestamp or a milliseconds value. Paste it into the epoch field and you will see the readable date immediately.