Unix Timestamp Converter

Unix timestamps are the shared time format behind logs, APIs, tokens, and schedulers. This converter lets you switch between epoch values and human-readable dates instantly, with timezone-aware output and support for both seconds and milliseconds. For schedule debugging, pair conversions with Cron Expression Parser. For authentication workflows, decode and inspect token claims in JWT Decoder. If you are estimating payload sizes around event streams, Byte Calculator is a useful companion.

How to Use

1. Paste a Unix timestamp to convert it into readable date/time output.
2. Choose seconds or milliseconds based on your source system.
3. Switch timezone views to confirm user-facing and server-facing times.
4. Use date input mode to generate a timestamp for APIs or test fixtures.
5. Copy values into logs, payloads, SQL queries, or debugging notes.

Always verify units first. A milliseconds value interpreted as seconds produces a date far in the future, while seconds interpreted as milliseconds may appear near 1970.

Features

Live Current Timestamp

See the current Unix timestamp updating in real-time. Never wonder what the current epoch time is again.

Multiple Timezone Support

Convert timestamps to any timezone including:

• UTC, EST, PST, CST
• European timezones (London, Paris, Berlin)
• Asian timezones (Tokyo, Shanghai, Singapore)
• And many more!

Bi-directional Conversion

• Timestamp → Date: Enter a Unix timestamp to see the human-readable date
• Date → Timestamp: Pick a date and time to get the Unix timestamp

Seconds & Milliseconds

Toggle between seconds (standard Unix time) and milliseconds (JavaScript Date.now()) with a single click.

Use Cases

API Contracts and Database Fields

Many systems store event times as integers to avoid locale ambiguity. Convert values quickly during debugging and integration reviews.

Job Scheduling and Monitoring

When tasks are configured in cron syntax, convert next run times from Cron Expression Parser into epoch values for alerting and event correlation.

Token Verification

JWT claims like iat, nbf, and exp are Unix timestamps. Decode token payloads in JWT Decoder, then validate timing assumptions here.

Event Stream Capacity Planning

High-frequency timestamps often appear in telemetry payloads. If payload volume is large, estimate transfer and storage impact with Byte Calculator.

Technical Details

Unix time counts elapsed seconds from 1970-01-01T00:00:00Z and is timezone-agnostic at storage level. Display formatting applies timezone context later. This makes epoch values stable for transport and comparison across systems.

Common pitfalls include mixing local time with UTC assumptions, interpreting milliseconds as seconds, and relying on platform-specific date parsing rules. For reliable integrations, keep timestamps in UTC, specify unit expectations in API contracts, and convert only at user-facing boundaries.

Systems using 32-bit signed integers for seconds face the Year 2038 boundary (2147483647). Most modern platforms use 64-bit values, but legacy dependencies may still require special handling.

What is a Unix Timestamp?

A Unix timestamp (also called Epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. This date is known as the “Unix Epoch.”

Why Use Unix Timestamps?

• Universal: Same value regardless of timezone
• Compact: Single integer vs. formatted date string
• Sortable: Easy to sort chronologically
• Portable: Works across all programming languages
• Precise: Can represent exact moments in time

Common Use Cases

API Development

APIs often use Unix timestamps for date fields because they’re timezone-agnostic and easy to parse in any language.

{
  "created_at": 1702569600,
  "updated_at": 1702656000
}

Database Storage

Storing dates as integers is more efficient and avoids timezone confusion.

Log Analysis

Unix timestamps make it easy to calculate time differences and sort log entries.

JWT Tokens

JSON Web Tokens use Unix timestamps for iat (issued at) and exp (expiration) claims.

Converting in Code

JavaScript

// Current timestamp (seconds)
Math.floor(Date.now() / 1000);

// Timestamp to Date
new Date(timestamp * 1000);

// Date to timestamp
Math.floor(date.getTime() / 1000);

Python

import time
from datetime import datetime

# Current timestamp
int(time.time())

# Timestamp to datetime
datetime.fromtimestamp(timestamp)

# Datetime to timestamp
int(datetime.timestamp())

PHP

// Current timestamp
time();

// Timestamp to date
date('Y-m-d H:i:s', $timestamp);

// Date to timestamp
strtotime('2024-12-14');

Notable Timestamps

The Year 2038 Problem

The Year 2038 problem (also called Y2K38) occurs because many systems store Unix timestamps as 32-bit signed integers. The maximum value (2,147,483,647) corresponds to January 19, 2038, at 03:14:07 UTC. After this moment, systems using 32-bit timestamps will overflow and show incorrect dates.

Modern systems use 64-bit integers which can represent dates billions of years into the future.

FAQ

Should I use seconds or milliseconds for Unix timestamps?

Use seconds for most APIs, databases, and JWT claims, and milliseconds for JavaScript runtime values like Date.now(). Confirm the expected unit before storing or comparing values.

Why does my converted time differ by a few hours?

Unix timestamps are UTC-based. Differences usually come from timezone display settings or daylight saving transitions rather than wrong timestamp math.

How are Unix timestamps used in JWT tokens?

JWT claims such as iat, nbf, and exp are numeric Unix timestamps in seconds. Converting them helps verify token age, validity windows, and expiration behavior.

Can Unix timestamps overflow?

Older 32-bit systems can overflow near January 2038. Modern 64-bit systems avoid this practical limit for normal application timelines.

Privacy Note

All conversions happen in your browser. No data is sent to any server.