How does it know if my number is seconds or milliseconds?

It checks the number of digits — 13 or more digits is treated as milliseconds, fewer as seconds.

What is a Unix timestamp?

It's the number of seconds (or milliseconds) that have elapsed since January 1, 1970, 00:00:00 UTC — a common way computers represent a point in time.

Is my date data sent anywhere?

No — conversion happens entirely in your browser.

Can I convert a negative timestamp (before 1970)?

Yes — negative Unix timestamps representing dates before 1970 are supported.

What if I enter an invalid date?

You'll see a clear error message asking for a valid date or timestamp.

Does this account for time zones?

Yes — results are shown in both UTC and your browser's detected local time zone.

Time & Date Tools

Timestamp Converter

Enter a date or a Unix timestamp and instantly see it converted into ISO 8601, UTC, local time and relative formats.

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Runs in Your Browser
Instant Results
100% Private

Your Text

Your result will appear here.

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What Is a Timestamp Converter?

This tool converts between human-readable dates and Unix timestamps automatically — paste in a date and get back its Unix timestamp, or paste in a Unix timestamp (seconds or milliseconds) and get back the matching calendar date, in ISO 8601, UTC and your local time zone.

It auto-detects which kind of input you've given it based on whether it looks like a number or a date string, and further guesses whether a numeric timestamp is in seconds or milliseconds based on its length — removing the need to specify a direction manually for most everyday use.

Who Uses This Tool?

For Business

Convert a Unix timestamp from a server log into a readable date.

For Personal Use

Figure out what date and time a timestamp in a file actually refers to.

For Students

Learn how Unix time works for a computer science course.

For Offices

Convert a timestamp from a database record into a human-readable date for a report.

Why Use This Tool

Key Features

Auto-Detects Direction

Paste either a date or a timestamp — it figures out which is which.

Multiple Output Formats

See ISO 8601, UTC, local time and a relative ("3 days ago") format at once.

Instant Conversion

Results update immediately as you type.

100% Private

Converted entirely in your browser — nothing is transmitted.

The Payoff

Benefits

No Direction to Choose

Works whether you have a date or a timestamp, without switching modes.

See Every Format at Once

ISO, UTC, local and relative time, all in one result.

No Software Needed

Convert directly in the browser — no script or spreadsheet formula required.

Step by Step

How to Use Timestamp Converter

Enter a Date or Timestamp

Type a date, or a Unix timestamp in seconds or milliseconds.

Read the Converted Result

See the matching value in every common format.

Copy the Format You Need

Use the Copy button to grab the ISO date and timestamp.

Specifications

Technical Details

Detail	Value
Input	Date strings or Unix timestamps (seconds or milliseconds)
Processing	Not applicable — single date/timestamp conversion
Output	Exact conversion using your browser's native Date object

You Can Verify This

Privacy & Security

What actually happens to your file when you use this tool.

100% Client-Side

This tool runs entirely inside your browser using JavaScript — nothing you type or generate is ever sent anywhere.

No Upload, Ever

There is no file upload and no server processing step — your data never leaves your device.

Works Offline

Once this page has loaded, the tool keeps working even without an internet connection.

Nothing Stored

Nothing you enter is saved on our servers — refreshing the page clears everything.

No Tracking of Your Input

We have no way to see what you type, generate or convert with this tool.

Get Better Results

Tips

A 10-Digit Number Is Usually Seconds

Most Unix timestamps in seconds are 10 digits (until the year 2286); 13 digits usually means milliseconds.

Use the Relative Time for Quick Sanity Checks

The "X days ago" style output is a quick way to confirm a timestamp is roughly what you expect.

Frequently Asked Questions