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Milliseconds To Date Converter - Free Online Tool

Convert Unix Timestamp to Date

Enter Unix timestamp (seconds or milliseconds)

Human-Readable Date

ISO 8601 Format

Unix Timestamp (milliseconds)

Unix Timestamp (seconds)

Last updated March 22, 2026

Common Millisecond Timestamp Sources

JavaScript: Date.now(), new Date().getTime(), performance.now()
Java: System.currentTimeMillis(), Instant.toEpochMilli()
Twitter/X API: tweet timestamps in some endpoint responses
Discord API: Snowflake ID timestamps (milliseconds since Discord epoch)
MongoDB: internal date storage format
Redis: TIME command returns seconds and microseconds
Payment APIs: transaction timestamps for sub-second precision

All conversion happens entirely in your browser. No timestamp data is sent to any server.

Examples

Example 1: Converting a JavaScript Timestamp

JavaScript's Date.now() returns the current time in milliseconds. Convert a JavaScript timestamp to a readable date:

Input: 1710000000000

Output:
  ISO 8601 (with ms):  2024-03-09T20:00:00.000Z
  ISO 8601:            2024-03-09T20:00:00Z
  UTC:                 Saturday, March 9, 2024 at 8:00:00 PM UTC
  Unix (seconds):      1710000000
  Relative:            about 1 year ago

Notice that the millisecond timestamp (13 digits) is exactly 1,000 times the equivalent second-precision Unix timestamp (10 digits). This 1000x difference is the most common source of timestamp bugs when mixing data from different systems.

Example 2: Identifying Seconds vs Milliseconds

A developer sees a timestamp in a database and is not sure if it is in seconds or milliseconds:

Timestamp: 1710000000   (10 digits → seconds)
Converts to: 2024-03-09 20:00:00 UTC ✅ (reasonable date)

Timestamp: 1710000000000  (13 digits → milliseconds)
Converts to: 2024-03-09 20:00:00 UTC ✅ (same date, correct)

Timestamp: 1710000000 treated as milliseconds:
Converts to: 1970-01-20 18:40:00 UTC ❌ (wrong — 1970 is a red flag)

The converter automatically detects the format based on magnitude. A 10-digit number is treated as seconds; a 13-digit number is treated as milliseconds. If a conversion produces a date in 1970, that is a strong signal the timestamp is in seconds but was treated as milliseconds.

Example 3: Converting Twitter/X API Timestamps

Twitter's API returns tweet creation times as millisecond timestamps in the created_at field of some endpoints:

Input: 1709900000000

Output:
  ISO 8601:   2024-03-08T15:13:20.000Z
  UTC:        Friday, March 8, 2024 at 3:13:20 PM UTC
  Local (ET): Friday, March 8, 2024 at 10:13:20 AM EST

When building Twitter integrations, millisecond timestamps appear frequently in API responses. The converter helps verify that your timestamp parsing code is producing the correct dates.

Frequently Asked Questions

How to convert Unix timestamp to date?

Enter the Unix timestamp (in seconds or milliseconds) and click Convert. The tool automatically detects the format and displays the date in multiple formats including ISO 8601.

What is a Unix timestamp?

A Unix timestamp is the number of seconds (or milliseconds) since January 1, 1970, 00:00:00 UTC. It's a universal time format used across programming languages and databases.