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Unix Timestamp Converter

A free, fast, and accurate tool to convert Unix timestamps (Epoch time) to human-readable dates. All conversions are done in your browser, ensuring your data remains private.

A Unix timestamp is the number of seconds that have elapsed since January 1, 1970 (00:00:00 UTC). It is a universal, timezone-independent way to represent a point in time, widely used in server logs, databases, and APIs. Understanding and using timestamps correctly is a fundamental skill in modern software development.

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A Deeper Dive into Unix Timestamps

What Exactly is a Unix Timestamp?

A Unix timestamp is a time representation method that indicates the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC (Coordinated Universal Time). This starting point is called the "Unix Epoch."

Because it is a simple integer that increments every second, it is a universal, timezone-independent way to represent a point in time. This makes it incredibly useful in server logs, databases, APIs, and any distributed system where synchronizing time is critical.

Why January 1, 1970?

The choice of this date was a convenient starting point for the developers of the Unix operating system in the early 1970s. It has since become the universal standard for time representation in most computer systems.

Precision Matters: Seconds vs. Milliseconds

Unix timestamps can have different precision levels. Confusing them is one of the most common bugs in software development. This tool auto-detects the precision of your input.

Seconds (s)10 digits

The most common format, used by many backend systems (PHP, Python, SQL).

Example
1640995200
Milliseconds (ms)13 digits

Standard in JavaScript (`Date.now()`). Essential for frontend development.

Example
1640995200000

The Most Common Timestamp Bug

Mistaking seconds for milliseconds is a frequent error. For example, passing a 10-digit timestamp to a function expecting 13 digits (like `new Date()` in JavaScript) will result in a date in early 1970, not the date you intended. Always check the precision required by your tools and APIs.

Timestamp Handling in JavaScript

A Practical Guide for Web Developers
JavaScript's native `Date` object operates with milliseconds. This is a critical detail when working with backends that use seconds.

1. Get the Current Unix Timestamp

Use `Date.now()` to get the current timestamp in milliseconds. To get it in seconds for a backend API, you must divide by 1000.

javascript
// Get current timestamp in MILLISECONDS (for frontend use)
const timestampInMs = Date.now();
console.log(timestampInMs); // Example: 1678886400123

// Get current timestamp in SECONDS (for backend APIs)
const timestampInSeconds = Math.floor(Date.now() / 1000);
console.log(timestampInSeconds); // Example: 1678886400

2. Convert a Unix Timestamp to a Date

If you receive a timestamp in seconds from an API, you must convert it to milliseconds by multiplying by 1000 before passing it to the `new Date()` constructor.

javascript
const timestampInSeconds = 1678886400;

// Multiply by 1000 to convert to milliseconds
const dateObject = new Date(timestampInSeconds * 1000);

console.log(dateObject.toISOString()); // "2023-03-15T13:20:00.000Z"

3. Convert a Date to a Unix Timestamp

To get the timestamp from a `Date` object, use the `.getTime()` method for milliseconds, or divide for seconds.

javascript
const myDate = new Date('2024-10-12T10:30:00Z');

// Get the timestamp in milliseconds
const timestampInMs = myDate.getTime();
console.log(timestampInMs); // 1728712200000

// To get the timestamp in seconds for a backend
const timestampInSeconds = Math.floor(myDate.getTime() / 1000);
console.log(timestampInSeconds); // 1728712200

Core Best Practices for Developers

Building Robust, Enterprise-Grade Systems
Handling timestamps correctly is crucial for data integrity and system reliability. Here are some key takeaways from our full guide.

Database Design

  • Store timestamps in UTC using a `BIGINT` for millisecond precision. Avoid timezone-aware database types.
  • Always create indexes on timestamp columns (`created_at`, `updated_at`) to ensure fast query performance for time-range lookups.
  • Avoid storing time as strings (`VARCHAR`). This makes querying, sorting, and timezone management extremely difficult and error-prone.

API Design

  • In JSON responses, provide both the Unix timestamp (e.g., `1678886400123`) and the ISO 8601 string (`"2023-03-15T13:20:00.123Z"`).
  • Your API should always return timestamps in UTC (indicated by the "Z" in the ISO string). Let the client handle timezone conversions.
  • For request parameters, be flexible. Allow users to query time ranges using timestamps or ISO date strings (e.g., `?since=2023-01-01`).
Need More Professional Tools & Guides?
We have prepared advanced features, API documentation, and development best practices to help you excel in a production environment.

Frequently Asked Questions (FAQ)

Why does my time seem off by a few hours?

This is usually a timezone issue. A Unix timestamp is always in UTC. Our tool shows both UTC time and your browser's local time. The difference you see is the offset between your local timezone and UTC.

Should I use a 10-digit or 13-digit timestamp?

10 digits represent seconds, while 13 digits represent milliseconds. The **JavaScript** ecosystem (front-end, Node.js) commonly uses milliseconds. **PHP, Python, Ruby, and SQL databases** often default to seconds. The key is to be consistent within your system and explicit about the precision when interacting with other systems.

What is the "Year 2038 Problem"?

On older 32-bit systems, the 32-bit signed integer used to store timestamps will overflow on January 19, 2038. Modern 64-bit systems and languages (including the tech used for this site) have solved this problem, so you can safely use them for centuries to come.

How do I convert a date back to a timestamp?

Our converter is bidirectional. In the "Date to Timestamp" tab, you can enter a human-readable date (e.g., `2024-10-26 10:00:00`), and the tool will generate the corresponding Unix timestamp.

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