Timestamp Converter: Complete Guide

Timestamps are fundamental to software development, data analysis, and system administration. This guide covers everything you need to know about converting and using timestamps.

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 (the Unix Epoch).

Example

1735689600 = January 1, 2025, 00:00:00 UTC

Why Use Timestamps?

Advantages

1. Universal: Same value worldwide, timezone-independent
2. Simple: Just a single integer number
3. Easy to Compare: Direct numerical comparison
4. Efficient Storage: Compact representation
5. Calculation-Friendly: Easy date arithmetic

Use Cases

• Log file timestamps
• Database record creation times
• API request/response timestamps
• Session expiration times
• File modification dates
• Event scheduling

Timestamp Formats

Unix Timestamp (Seconds)

1735689600

Used by: PHP, Python, C, most Unix systems

Unix Timestamp (Milliseconds)

1735689600000

Used by: JavaScript, Java, many APIs

ISO 8601 Format

2025-01-01T00:00:00Z
2025-01-01T00:00:00+00:00

Standard international format, used in JSON APIs

RFC 2822 Format

Wed, 01 Jan 2025 00:00:00 +0000

Used in email headers, HTTP dates

Human-Readable Formats

January 1, 2025 12:00 AM
01/01/2025 00:00:00
2025-01-01 00:00:00

Converting Timestamps

Unix to Human-Readable

JavaScript

const timestamp = 1735689600;
const date = new Date(timestamp * 1000);
console.log(date.toLocaleString());

Python

import datetime
timestamp = 1735689600
date = datetime.datetime.fromtimestamp(timestamp)
print(date.strftime('%Y-%m-%d %H:%M:%S'))

PHP

$timestamp = 1735689600;
echo date('Y-m-d H:i:s', $timestamp);

Human-Readable to Unix

JavaScript

const date = new Date('2025-01-01T00:00:00Z');
const timestamp = Math.floor(date.getTime() / 1000);

Python

import datetime
date = datetime.datetime(2025, 1, 1, 0, 0, 0)
timestamp = int(date.timestamp())

PHP

$date = '2025-01-01 00:00:00';
$timestamp = strtotime($date);

Working with Timezones

Important Concepts

• Unix timestamps are always UTC
• Timezone conversion happens during display
• Store timestamps in UTC, display in local timezone

JavaScript Timezone Handling

// Get current timestamp
const now = Date.now() / 1000;

// Convert to specific timezone
const options = {
  timeZone: 'America/New_York',
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit'
};
const formatted = new Date(now * 1000).toLocaleString('en-US', options);

Python Timezone Handling

from datetime import datetime
import pytz

# Create timezone-aware datetime
utc = pytz.UTC
eastern = pytz.timezone('US/Eastern')

# Convert
utc_time = datetime.now(utc)
eastern_time = utc_time.astimezone(eastern)

Common Timestamp Operations

Current Timestamp

JavaScript

const now = Math.floor(Date.now() / 1000);

Python

import time
now = int(time.time())

PHP

$now = time();

MySQL

SELECT UNIX_TIMESTAMP();

Adding/Subtracting Time

JavaScript

const timestamp = 1735689600;
const tomorrow = timestamp + (24 * 60 * 60); // +1 day
const lastWeek = timestamp - (7 * 24 * 60 * 60); // -7 days

Python

from datetime import datetime, timedelta
timestamp = 1735689600
date = datetime.fromtimestamp(timestamp)
tomorrow = date + timedelta(days=1)

Time Differences

const start = 1735689600;
const end = 1735776000;
const diffSeconds = end - start;
const diffHours = diffSeconds / 3600;
const diffDays = diffSeconds / 86400;

Database Timestamps

MySQL/MariaDB

-- Store as integer
CREATE TABLE events (
  id INT,
  created_at INT,
  INDEX idx_created (created_at)
);

-- Or use TIMESTAMP type
CREATE TABLE events (
  id INT,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Convert to Unix timestamp
SELECT UNIX_TIMESTAMP(created_at) FROM events;

PostgreSQL

-- Store as integer
CREATE TABLE events (
  id SERIAL,
  created_at BIGINT
);

-- Or use TIMESTAMP
CREATE TABLE events (
  id SERIAL,
  created_at TIMESTAMP DEFAULT NOW()
);

-- Convert to Unix timestamp
SELECT EXTRACT(EPOCH FROM created_at)::INTEGER FROM events;

MongoDB

// MongoDB uses milliseconds
db.events.insertOne({
  name: "Event",
  created_at: new Date()
});

// Query by timestamp
db.events.find({
  created_at: { $gte: new Date(1735689600000) }
});

Best Practices

1. Always Store in UTC

• Store all timestamps in UTC
• Convert to local timezone only for display
• Avoid timezone-specific storage

2. Use Consistent Units

• Choose seconds OR milliseconds
• Document which unit you're using
• Be consistent across your application

3. Handle Timezones Properly

• Never assume user's timezone
• Let users select their timezone
• Display times with timezone indicator

4. Consider Precision

• Seconds: sufficient for most applications
• Milliseconds: needed for high-precision logging
• Microseconds: used in performance monitoring

5. Validate Timestamps

function isValidTimestamp(timestamp) {
  // Check if reasonable (between 1970 and 2100)
  return timestamp > 0 && timestamp < 4102444800;
}

Common Mistakes

1. Mixing Seconds and Milliseconds

// Wrong
const date = new Date(1735689600); // Missing * 1000

// Correct
const date = new Date(1735689600 * 1000);

2. Forgetting Timezone Conversion

// Wrong - assumes local timezone
const date = new Date('2025-01-01 00:00:00');

// Correct - explicit UTC
const date = new Date('2025-01-01T00:00:00Z');

3. Year 2038 Problem

• 32-bit systems can't represent dates after 2038
• Use 64-bit timestamps for future dates
• Consider using BIGINT in databases

Timestamp Ranges

Minimum and Maximum Values

32-bit (seconds)

• Min: -2,147,483,648 (December 13, 1901)
• Max: 2,147,483,647 (January 19, 2038)

64-bit (seconds)

• Practically unlimited range
• Recommended for all new applications

Use Our Timestamp Converter

Our free online tool provides:

• Instant conversions
• Multiple format support
• Timezone handling
• Batch conversion
• Human-readable output
• Copy to clipboard

Convert timestamps effortlessly today!