Current Time
Timestamp → Date
Quick Reference
What are Unix Timestamps?
Unix timestamps (also known as Epoch time or POSIX time) are a standardized way of representing time across all computer systems. Instead of using dates and times in human-readable formats (like "January 15, 2025 3:30 PM"), Unix timestamps represent time as a single number: the count of seconds that have elapsed since the Unix Epoch.
The Unix Epoch
The Unix Epoch is the starting point for all Unix timestamps:
This arbitrary starting point was chosen when Unix was being developed in the early 1970s. Every Unix timestamp counts forward (or backward for dates before 1970) from this moment.
Key Characteristics
Timezone Independent
Unix timestamps are always in UTC (Coordinated Universal Time). This eliminates confusion caused by timezones, daylight saving time, and regional date formats.
Simple Arithmetic
Calculating time differences is as simple as subtracting two numbers. Want to know how many seconds between two events? Just subtract their timestamps.
Compact Storage
A timestamp requires only 4 bytes (32-bit) or 8 bytes (64-bit) of storage, compared to string-based date formats that can require 20+ bytes.
Universal Standard
Supported by virtually every programming language, database system, and operating system, making timestamps ideal for cross-platform data exchange.
Common Use Cases
Database Storage
Store created_at, updated_at, and deleted_at timestamps in databases for efficient queries and sorting.
WHERE created_at > 1700000000
API Authentication
Generate time-based tokens, validate expiration times, and implement OAuth flows with precise timestamp validation.
// Token expired
}
Analytics & Logging
Track user activity, measure performance metrics, and analyze event sequences with precise timing.
duration: 2.547 seconds
user_id: 12345
Distributed Systems
Synchronize events across servers in different timezones, order distributed transactions, and implement event sourcing.
server: "us-east-1" }
Scheduling & Cron Jobs
Schedule future tasks, implement countdown timers, and trigger time-based automation with exact precision.
interval: 86400
Cache Invalidation
Implement TTL (time-to-live) for cached data, expire sessions, and manage temporary resources efficiently.
invalidateCache()
}
Conversion Examples
Timestamp to Date Conversions
| Unix Timestamp | Human-Readable Date (UTC) | Description |
|---|---|---|
| 0 | January 1, 1970 at 12:00:00 AM | The Unix Epoch |
| 1000000000 | September 9, 2001 at 1:46:40 AM | First 1 billion seconds |
| 1234567890 | February 13, 2009 at 11:31:30 PM | Popular test timestamp |
| 1700000000 | November 14, 2023 at 10:13:20 PM | Round billion milestone |
| 2147483647 | January 19, 2038 at 3:14:07 AM | Max 32-bit timestamp |
Common Programming Patterns
JavaScript / TypeScript
// Get current timestamp (seconds)
const now = Math.floor(Date.now() / 1000);
// Convert timestamp to date
const date = new Date(1700000000 * 1000);
// Convert date to timestamp
const timestamp = Math.floor(date.getTime() / 1000);Python
import time
from datetime import datetime
# Get current timestamp
now = int(time.time())
# Convert timestamp to date
date = datetime.fromtimestamp(1700000000)
# Convert date to timestamp
timestamp = int(datetime.now().timestamp())PHP
// Get current timestamp
$now = time();
// Convert timestamp to date
$date = date('Y-m-d H:i:s', 1700000000);
// Convert date to timestamp
$timestamp = strtotime('2023-11-14 22:13:20');MySQL / SQL
-- Get current timestamp
SELECT UNIX_TIMESTAMP();
-- Convert timestamp to date
SELECT FROM_UNIXTIME(1700000000);
-- Convert date to timestamp
SELECT UNIX_TIMESTAMP('2023-11-14 22:13:20');Frequently Asked Questions
Find answers to common questions
Need Help with Time-Based Systems?
Our development team can help you build robust time-tracking systems, implement timezone-aware applications, and optimize database timestamp queries.