Unix Timestamp Converter

A log file contains 1710345600 next to an error message. Is that seconds or milliseconds? What day was that? You need a fast converter that auto-detects the precision, shows the date in multiple formats, and lets you paste a batch of timestamps from a log dump.

What Is a Unix Timestamp?

A Unix timestamp is the number of seconds since January 1, 1970, 00:00:00 UTC — the Unix epoch. It is a single integer that represents an exact moment in time, independent of timezone or locale. Every major programming language and operating system uses this format internally.

Seconds vs. Milliseconds

Unix timestamps originally count seconds (10 digits for current dates). JavaScript and many modern APIs use milliseconds (13 digits). This tool auto-detects which format you entered:

• 10 digits (< 10^12) → treated as seconds
• 13 digits (>= 10^12) → treated as milliseconds

Output Formats

Conversion Modes

Timestamp to Date. Paste a Unix timestamp and instantly see it in all output formats. Select any IANA timezone for the local time display.

Date to Timestamp. Enter a human-readable date in ISO 8601, RFC 2822, or natural format and get the epoch seconds and milliseconds.

Live Clock. See the current Unix timestamp updating in real time. Useful for quick reference when debugging or writing time-dependent code.

Batch Mode. Paste multiple timestamps, one per line, and convert them all at once. Each line shows the original value, detected precision, ISO date, and relative time.

Getting Timestamps in Code

// JavaScript
Date.now()              // milliseconds
Math.floor(Date.now() / 1000)  // seconds

# Python
import time
int(time.time())        # seconds

# Bash
date +%s                # seconds

The Year 2038 Problem

Systems storing timestamps as signed 32-bit integers will overflow on January 19, 2038 at 03:14:07 UTC. The maximum 32-bit value is 2,147,483,647. Modern systems use 64-bit integers, which extend the range to approximately year 292 billion.

Privacy

All conversions run entirely in your browser. No timestamps or dates are transmitted to any server.

Frequently Asked Questions

What is epoch time zero? The Unix epoch is midnight January 1, 1970, UTC. All Unix timestamps count from this reference point. Negative timestamps represent dates before 1970.

Can I convert negative timestamps? Yes. Negative timestamps represent dates before the Unix epoch (January 1, 1970). For example, -86400 is December 31, 1969.

How precise are Unix timestamps? Standard Unix timestamps have second-level precision. Millisecond timestamps (13 digits) provide 1/1000 second resolution. For microsecond or nanosecond precision, specialized APIs are needed.

Why is the Unix epoch January 1, 1970? When Unix was designed at Bell Labs in the early 1970s, the engineers chose a recent round-number year as the reference point. 1970 was close to the system’s creation date and far enough in the past to be practical.

Is my data sent to a server? No. All timestamp conversions happen entirely in your browser using JavaScript. No data leaves your device.