Unix Time Converter: Convert Timestamps to Dates and Back

Working with Unix timestamps is a daily task for developers, system administrators, and anyone dealing with server logs, APIs, or databases. Our Unix Time Converter makes it instant and painless to translate between Unix timestamps and human-readable dates—no mental math or confusing documentation required.

How to Use

Enter your input in the main field—paste a Unix timestamp (seconds or milliseconds), ISO 8601 date, or any standard date string
Auto-detection instantly recognizes the format and converts it to all supported formats
Click “Now” to get the current timestamp in all formats
Add timezones using the timezone selector to compare times across regions (selections are saved automatically)
Click any result to copy it to your clipboard instantly

What is Unix Time?

Unix time (also called Epoch time or POSIX time) counts the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, not counting leap seconds. It’s the universal standard for representing time in computer systems because it’s simple, sortable, and timezone-agnostic. Some systems use milliseconds instead of seconds—our tool handles both automatically.

Supported Formats

Input formats:

Unix timestamp in seconds (e.g., 1735689600)
Unix timestamp in milliseconds (e.g., 1735689600000)
ISO 8601 date strings (e.g., 2025-01-01T00:00:00Z)
Human-readable date strings (e.g., January 1, 2025)

Output formats:

Local time in your timezone
UTC/ISO 8601 format
Unix timestamp (seconds)
Unix timestamp (milliseconds)
Relative time (e.g., “2 hours ago”)
Day of year, week of year, leap year indicator
RFC 2822 format (email headers)
Multiple custom timezones

Common Use Cases

Debugging server logs that use Unix timestamps
API development when working with timestamp fields
Database queries filtering by date ranges
Testing time-sensitive features in applications
Converting between timezones for distributed teams
Understanding timestamps in GitHub commits, blockchain transactions, or system events
Planning deployments across different time zones

Frequently Asked Questions

What’s the difference between Unix seconds and milliseconds? Unix time traditionally uses seconds, but JavaScript and many modern APIs use milliseconds for finer precision. Our tool auto-detects which you’re using based on the number’s magnitude (13 digits = milliseconds, 10 digits = seconds).

Why does my timestamp show the wrong date? Double-check if you’re using seconds or milliseconds. If you paste a seconds timestamp but your system expects milliseconds (or vice versa), you’ll be off by a factor of 1,000.

Are timezones saved between sessions? Yes. Any timezones you add are stored in your browser’s local storage, so they’ll still be there when you return.

What happens on January 19, 2038? The “Year 2038 problem” occurs when 32-bit signed integers can no longer represent Unix time (they max out at 2,147,483,647 seconds). Modern 64-bit systems don’t have this issue and can represent dates billions of years into the future.

Try our free Unix Time Converter tool now.