Unix Timestamp Converter

Paste any timestamp or date. The tool detects the format automatically and shows it in every common representation. Live "now" clock at the top, ticking every second.

What it accepts

• Unix seconds — 1735689600 (10-digit)
• Unix milliseconds — 1735689600000 (13-digit)
• Microseconds / nanoseconds — high-precision database timestamps; converted down to ms
• ISO 8601 — 2025-01-01T00:00:00Z or 2025-01-01T09:00:00+09:00
• RFC 2822 — Wed, 01 Jan 2025 00:00:00 GMT (HTTP and email date format)
• Plain dates — 2025-01-01 (interpreted as midnight UTC)

What you get back

Every format you might need, side by side:

• Unix seconds and milliseconds (most common)
• ISO 8601 UTC and your local timezone
• RFC 2822 (for HTTP Date: headers and email)
• Day of the week
• Relative time ("3 days ago", "in 2 hours")
• JavaScript new Date(...) constructor form

The seconds-vs-milliseconds confusion

The single most common bug in date code: passing a number meant for milliseconds (or vice versa) to a function expecting the other unit. A 1000× magnitude error gives you a date 30+ years off. See our dedicated guide on this.

Y2038 — the next big rollover

Quick test: paste 2147483647. That's the maximum value of a signed 32-bit integer — and the moment when 32-bit Unix timestamps overflow. It corresponds to 2038-01-19 03:14:07 UTC. Any system still using time_t as a 32-bit value (some embedded systems, old databases, legacy file formats) will roll over to 1901 at that moment. Full discussion →

How this compares to other epoch converters

unixtimestamp.com and epochconverter.com have ranked at the top for "epoch converter" for over a decade. They're fine but slow, ad-laden, and lack auto-detection — you have to tell them whether your input is seconds or milliseconds.

This tool: smaller bundle, auto-detection, live "now" clock, no upload, all your output formats visible at once.

Programmatic equivalents

// JavaScript / Node
Date.now();                                      // ms
Math.floor(Date.now() / 1000);                   // seconds
new Date(1735689600 * 1000).toISOString();       // sec → ISO

// Python
import time
time.time()                                      // seconds (float)
import datetime
datetime.datetime.now(datetime.timezone.utc).isoformat()

// Bash
date +%s                                         // seconds
date +%s%3N                                      // milliseconds (GNU)
date -u -d @1735689600 '+%Y-%m-%dT%H:%M:%SZ'     // sec → ISO

// Go
time.Now().Unix()                                // seconds
time.Now().UnixMilli()                           // milliseconds

Common pitfalls

• JavaScript dates are millisecond-based. Date.now() returns ms, not seconds. Forgetting to divide by 1000 is the most common bug.
• Some APIs use seconds (most), some use milliseconds (JavaScript). When integrating, check the docs.
• Negative timestamps are valid. -86400 is 1969-12-31 UTC. Most systems handle them, but some (older embedded) clamp to 0.
• Leap seconds aren't represented in Unix time. Unix time skips them; ISO 8601 can include them (23:59:60) but most parsers reject the literal.
• Timezone matters for date-only strings. "2025-01-01" parses as UTC midnight in some libraries, local midnight in others. Always include a time + timezone for unambiguous parsing.