Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa. Supports seconds, milliseconds, and multiple timezones. All processing happens in your browser for complete privacy.
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About Unix Timestamps
Unix timestamp (also known as Epoch time) is a system for tracking time as a running total of seconds since January 1, 1970 00:00:00 UTC (the Unix Epoch).
- Seconds: Standard Unix timestamp (10 digits)
- Milliseconds: JavaScript timestamp (13 digits)
- Microseconds: High-precision timestamp (16 digits)
- Nanoseconds: Ultra-precise timestamp (19 digits)
What is a Unix Timestamp?
A Unix timestamp (also called Epoch time, POSIX time, or Unix time) is a system for tracking time as a running total of seconds. It counts the number of seconds that have elapsed since the Unix Epoch: January 1, 1970 at 00:00:00 UTC (Coordinated Universal Time). This specific moment is also known as the "birth of Unix time" and serves as the reference point for all Unix timestamp calculations.
The Unix timestamp system was originally developed for Unix operating systems, hence the name, but it has since become a universal standard adopted across virtually all modern computing platforms, programming languages, and databases. The beauty of Unix timestamps lies in their simplicity: a single integer represents an exact moment in time, making them incredibly efficient for storage, comparison, and computation.
Unlike human-readable date formats that vary by locale, language, and timezone, Unix timestamps are completely unambiguous and universal. Whether you're in New York, Tokyo, or Sydney, the Unix timestamp 1701388800 represents exactly the same moment in time for everyone. This universality makes Unix timestamps essential for distributed systems, international applications, and any software that needs to handle time consistently across different locations.
One important characteristic of Unix timestamps is that they don't account for leap seconds—small adjustments made to keep atomic time synchronized with Earth's rotation. This means Unix time assumes every day has exactly 86,400 seconds, which simplifies calculations but means Unix time can drift slightly from actual solar time over long periods.
Understanding Different Timestamp Formats
Seconds (10 digits)
The standard Unix timestamp format counting seconds since the Unix Epoch. This is the most common format, used by most Unix systems, Linux, macOS, and many programming languages like Python, PHP, and C.
Milliseconds (13 digits)
JavaScript's native timestamp format, counting milliseconds since the Unix Epoch. Used extensively in web development, Node.js, and any JavaScript-based applications. Provides millisecond precision.
Microseconds (16 digits)
High-precision timestamps counting microseconds (millionths of a second) since the Unix Epoch. Used in performance monitoring, high-frequency trading systems, and scientific applications requiring precise timing.
Nanoseconds (19 digits)
Ultra-high precision timestamps counting nanoseconds (billionths of a second) since the Unix Epoch. Essential for distributed systems, real-time trading, and applications requiring nanosecond-level timing accuracy.
Common Use Cases for Unix Timestamps
Database Storage and Queries
Databases use Unix timestamps to store date and time information efficiently. They're perfect for sorting chronological records, calculating time differences, and performing date-based queries. Most SQL databases (MySQL, PostgreSQL, SQLite) and NoSQL databases (MongoDB, Redis) support Unix timestamps natively, making them ideal for created_at, updated_at, and expires_at fields.
API Responses and Data Exchange
RESTful APIs and data exchange formats (JSON, XML) frequently use Unix timestamps to represent dates. They eliminate timezone confusion and ambiguity in international applications. Since Unix timestamps are just integers, they're easy to serialize, deserialize, and validate across different systems and programming languages.
Session Management and Authentication
Web applications use Unix timestamps to manage user sessions, JWT tokens, and authentication expiration times. The exp (expiration) claim in JSON Web Tokens (JWT) uses Unix timestamps to determine when a token should no longer be accepted. Cookie expiration, cache invalidation, and temporary access links also rely on Unix timestamps.
Logging and Monitoring Systems
Server logs, application logs, and monitoring systems timestamp every event using Unix time. This enables precise troubleshooting, performance analysis, and correlation of events across distributed systems. Log aggregation tools like Elasticsearch, Splunk, and CloudWatch all use Unix timestamps for indexing and time-series analysis.
Scheduled Tasks and Cron Jobs
Task schedulers, cron jobs, and background workers use Unix timestamps to schedule future execution, track last run times, and calculate intervals between executions. Whether you're scheduling email campaigns, database backups, or automated reports, Unix timestamps provide reliable scheduling across different timezones.
Cache Invalidation and TTL
Caching systems like Redis, Memcached, and CDN edge servers use Unix timestamps to implement Time-To-Live (TTL) mechanisms. They determine when cached data should expire and be refreshed. HTTP headers like Expires and Last-Modified also use timestamp formats derived from Unix time for browser cache control.
The Year 2038 Problem (Y2038)
The Year 2038 problem (also called Y2K38 or the Unix Millennium Bug) is a critical issue affecting systems that store Unix timestamps as signed 32-bit integers. On January 19, 2038 at 03:14:07 UTC, the Unix timestamp will reach 2,147,483,647—the maximum value for a signed 32-bit integer. One second later, the timestamp will overflow and wrap around to -2,147,483,648, representing December 13, 1901.
This overflow will cause catastrophic failures in any system still using 32-bit timestamps. Applications might incorrectly sort events, fail to process future dates, crash entirely, or produce completely nonsensical results. Financial systems could miscalculate interest, IoT devices might malfunction, embedded systems in vehicles and infrastructure could fail, and historical records could be corrupted.
The solution is to migrate to 64-bit timestamps, which can represent dates far into the future (until the year 292,277,026,596). Modern operating systems, databases, and programming languages have already made this transition. However, legacy systems, embedded devices, firmware, and older software still need updates before 2038.
Unlike the Y2K bug which was primarily a display issue, Y2038 is a fundamental arithmetic overflow that will break actual functionality. Organizations should audit their systems now, especially IoT devices, industrial control systems, medical equipment, and any hardware with long lifecycles that might still be in use by 2038.
Common Date Format Standards
ISO 8601 (International Standard)
The international standard for representing dates and times, designed to reduce ambiguity and confusion. Format: YYYY-MM-DDTHH:mm:ss.sssZ where Z indicates UTC timezone. This is the recommended format for data exchange and storage.
RFC 2822 (Email and HTTP Headers)
Used in email headers (Date field) and HTTP headers. More human-readable than ISO 8601 but less precise. Includes abbreviated day name, month, and timezone offset. Common in SMTP and HTTP protocols.
RFC 3339 (Internet Timestamp)
A profile of ISO 8601 specifically for Internet protocols. Similar to ISO 8601 but with stricter formatting rules and explicit timezone handling. Widely used in JSON APIs, OAuth, and modern web services.
Frequently Asked Questions
How do I get the current Unix timestamp?
In JavaScript: Math.floor(Date.now() / 1000) for seconds or Date.now() for milliseconds. In Python: import time; time.time(). In PHP: time(). In MySQL: SELECT UNIX_TIMESTAMP(). All return the current Unix timestamp in seconds (except JavaScript Date.now which returns milliseconds).
Why does my timestamp have 13 digits instead of 10?
A 13-digit timestamp represents milliseconds since the Unix Epoch, which is the native format used by JavaScript's Date object. The standard Unix timestamp has 10 digits (seconds). To convert milliseconds to seconds, divide by 1000. To convert seconds to milliseconds, multiply by 1000. Our tool automatically detects the format based on the number of digits and converts accordingly.
Do Unix timestamps include timezone information?
No, Unix timestamps are always in UTC (Coordinated Universal Time) and don't store timezone information. They represent an absolute point in time that's the same everywhere in the world. When converting to human-readable dates, you need to specify the timezone for display purposes. This is why 1701388800 represents the exact same moment for everyone, but might display as "Dec 1, 2023 00:00:00" in UTC, "Nov 30, 2023 19:00:00" in New York (EST), or "Dec 1, 2023 09:00:00" in Tokyo (JST).
Can Unix timestamps be negative?
Yes, negative Unix timestamps represent dates before the Unix Epoch (January 1, 1970). For example, -86400 represents December 31, 1969 00:00:00 UTC. Many programming languages and systems support negative timestamps for historical dates, though some older systems only support positive values. Be cautious when working with dates before 1970, as not all systems handle negative timestamps consistently.
How accurate are Unix timestamps?
Standard Unix timestamps (in seconds) are accurate to 1 second. Millisecond timestamps provide accuracy to 1/1000th of a second. For applications requiring higher precision, use microsecond (1/1,000,000th) or nanosecond (1/1,000,000,000th) timestamps. However, note that actual system clock accuracy depends on hardware, NTP synchronization, and operating system capabilities. Most servers maintain accuracy within milliseconds using NTP (Network Time Protocol).
What's the difference between Unix time and UTC time?
Unix time is a numeric representation (seconds since Epoch), while UTC (Coordinated Universal Time) is the timezone standard and time scale. Unix timestamps are always based on UTC—they count seconds since January 1, 1970 00:00:00 UTC. When you convert a Unix timestamp to a human-readable date, you can display it in any timezone, but the underlying timestamp always references UTC as its basis.
Why do some timestamps fail to convert?
Common reasons include: (1) The number is too large or too small to represent a valid date, (2) You're using the wrong format (seconds vs milliseconds), (3) The timestamp represents a date outside the supported range (typically 1970-2100), (4) There are non-numeric characters in the input, or (5) The date string format isn't recognized. Try checking if you need to divide or multiply by 1000 to convert between seconds and milliseconds.
Do Unix timestamps account for leap seconds?
No, Unix time does not account for leap seconds. It assumes every day has exactly 86,400 seconds. When a leap second occurs (added to keep atomic time synchronized with Earth's rotation), Unix time essentially "repeats" a second or pauses briefly. This design decision was made to keep Unix time calculations simple and predictable. For applications requiring precise astronomical time, you need specialized time libraries that handle leap seconds explicitly.
Is this timestamp converter free to use?
Yes, this Unix timestamp converter is completely free with no limitations, registration requirements, or usage fees. Convert as many timestamps as you need for personal or commercial projects. All conversions happen entirely in your browser using JavaScript—no data is sent to our servers, ensuring complete privacy and security. You can even use the tool offline once the page is loaded.
What date formats can I enter for conversion to timestamp?
Our converter accepts most common date formats including: ISO 8601 (2024-12-01, 2024-12-01T12:00:00Z), US format (12/1/2024, 12-1-2024), European format (1/12/2024, 1.12.2024), written format (December 1, 2024, Dec 1 2024, 1 Dec 2024), and combined formats with time (2024-12-01 12:00:00, Dec 1, 2024 12:00 PM). The tool uses JavaScript's Date.parse() which is very flexible, but for best results use ISO 8601 format (YYYY-MM-DD).
Programming Examples
JavaScript / TypeScript
const seconds = Math.floor(Date.now() / 1000);
const milliseconds = Date.now();const date = new Date(1701388800 * 1000);
console.log(date.toISOString());const timestamp = Math.floor(new Date('2024-12-01').getTime() / 1000);Python
import time
timestamp = int(time.time())from datetime import datetime
date = datetime.fromtimestamp(1701388800)
print(date.isoformat())from datetime import datetime
dt = datetime(2024, 12, 1)
timestamp = int(dt.timestamp())PHP
$timestamp = time();$date = date('Y-m-d H:i:s', 1701388800);$timestamp = strtotime('2024-12-01');SQL Databases
SELECT UNIX_TIMESTAMP();SELECT FROM_UNIXTIME(1701388800);SELECT EXTRACT(EPOCH FROM NOW());Related Developer Tools
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