What is the Year 2038 problem?

The Year 2038 problem affects systems storing Unix timestamps as signed 32-bit integers, which will overflow on January 19, 2038.

How do I know if my timestamp is in seconds or milliseconds?

Count the digits. Current timestamps in seconds have 10 digits. Millisecond timestamps have 13 digits.

Why does my timestamp show a different date than expected?

This is usually a timezone issue. Unix timestamps are in UTC; your browser applies your local timezone offset.

Why do some systems use milliseconds?

Millisecond timestamps provide higher precision for applications where events can happen multiple times per second.

100% Client-Side

Unix Timestamp Converter

Convert between Unix epoch timestamps and human-readable dates instantly. Support for both seconds and milliseconds precision, with automatic detection and timezone handling. All conversions happen locally in your browser.

Open Timestamp Converter

Key Features

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Bidirectional Conversion

Convert Unix timestamps to dates and dates back to Unix timestamps with equal ease.

🎯

Auto-Detection

Automatically detects whether your timestamp is in seconds or milliseconds and converts accordingly.

🌍

Timezone Support

View timestamps in your local timezone or convert to UTC. Understand how timezones affect your data.

📅

Multiple Formats

Output in various date formats including ISO 8601, RFC 2822, and custom readable formats.

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Live Clock

See the current Unix timestamp updating in real-time, useful for development and testing.

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Privacy-First

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

Understanding Unix Timestamps

What is a Unix Timestamp?

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

                        Unix Epoch:  0           → January 1, 1970 00:00:00 UTC

                        1 hour:      3600        → January 1, 1970 01:00:00 UTC

                        1 day:       86400       → January 2, 1970 00:00:00 UTC

                        Now:         1739145600  → February 9, 2026 (approximately)

Unix timestamps are used universally in computing because they're timezone-independent, easy to compare mathematically, and compact to store.

Seconds vs. Milliseconds

Most Unix timestamps are in seconds (10 digits for current dates). JavaScript and some APIs use milliseconds (13 digits). Our tool auto-detects which format you're using. A 10-digit number like 1739145600 is seconds; a 13-digit number like 1739145600000 is milliseconds.

How to Use

Enter Your Timestamp or Date

Paste a Unix timestamp (seconds or milliseconds) to convert it to a readable date, or enter a date to get its Unix timestamp equivalent.

Choose Your Format

Select the output format you need: seconds, milliseconds, ISO 8601, or human-readable. Adjust timezone settings if needed.

Copy and Use

Copy the converted value with a single click and use it in your application, database, or documentation.

Common Use Cases

Database Debugging

Convert timestamps stored in databases to human-readable dates for debugging and data analysis.

API Development

Verify that your API is sending and receiving timestamps in the correct format.

Log Analysis

Convert timestamps in log files to understand when events occurred.

JWT Expiration

Decode JWT token expiration times (exp claim) to understand when tokens expire.

Scheduling

Convert future dates to Unix timestamps for scheduling systems and cron jobs.

Data Migration

Convert between different date formats when migrating data between systems.

Frequently Asked Questions

The Year 2038 problem affects systems that store Unix timestamps as signed 32-bit integers. These systems will overflow on January 19, 2038, when the timestamp exceeds 2,147,483,647. Modern systems use 64-bit integers which won't overflow for billions of years. Our tool handles dates well beyond 2038.

Count the digits. Current timestamps in seconds have 10 digits (like 1739145600). Millisecond timestamps have 13 digits (like 1739145600000). Our tool automatically detects the format based on the magnitude of the number and converts accordingly.

This is usually a timezone issue. Unix timestamps are always in UTC. When you convert to a local date, your browser applies your local timezone offset. Make sure you understand whether you're looking at UTC or local time. Our tool clearly labels which timezone is being displayed.

Yes! Negative timestamps represent dates before the Unix Epoch (January 1, 1970). For example, -86400 represents December 31, 1969. This is useful for historical data, though very old dates may have reduced precision.

Unix time is a single integer counting seconds since 1970. ISO 8601 is a human-readable string format like "2026-02-09T12:00:00Z". Unix time is more compact and easier for computers to compare; ISO 8601 is more readable and includes timezone information explicitly.

Millisecond timestamps provide higher precision, which is important for applications where events can happen multiple times per second. JavaScript's Date.now() returns milliseconds, as do many modern APIs. Database systems often support microsecond or nanosecond precision as well.

Known limitations

— The milliseconds/seconds detection is a heuristic based on value magnitude — it's right most of the time but not guaranteed. When in doubt, check your data source.
— Doesn't support nanosecond precision. If you're working with Go's time.UnixNano() output, divide by 1,000,000 first.
— Historical timezone DST offsets before 1970 may be inaccurate — this is a limitation of the browser's Intl API, not specific to this tool.