📖 Online Timestamp Converter: Unix Timestamp ↔ UTC

Unix timestamp is the standard way computers record time – the number of seconds since January 1, 1970 (UTC/GMT midnight). ng.cc's timestamp converter supports automatic detection of second‑based (10‑digit) and millisecond‑based (13‑digit) timestamps, converts to UTC and back, all without leaving your browser. No server‑side processing, complete privacy.

🔄 Bidirectional conversion

Timestamp → UTC / UTC → timestamp. One‑click conversion and copy results.

⚡ Auto‑detect length

10 digits → seconds; 13 digits → milliseconds. Result clearly labelled.

🌍 Pure UTC standard

All calculations are based on UTC, free from timezone confusion. Perfect for server logs, global teams.

🔒 Local computation

All conversion runs in your browser – your data never leaves your device.

🎯 Timestamp Use Cases

📋 Server log analysis: Nginx/Apache logs use second timestamps; convert to readable times for debugging.
🔐 JWT token debugging: Fields like iat/exp are second timestamps; verify token validity.
📊 Database time fields: MySQL TIMESTAMP, MongoDB ObjectId embed timestamp info.
⏰ API debugging: Check the actual time of returned timestamps to confirm data freshness.
📱 Cross‑timezone collaboration: Use UTC as the intermediate format to avoid timezone errors.

💡 Timestamp FAQ

🔹 10‑digit vs 13‑digit timestamps

10‑digit timestamp: unit = seconds, Unix standard. e.g., 1700000000 → 2023-11-15 06:13:20 UTC.
13‑digit timestamp: unit = milliseconds, returned by JavaScript Date.now(). e.g., 1700000000000 → 2023-11-15 06:13:20.000 UTC.

🔹 Why UTC instead of local time?

Unix epoch 1970-01-01 00:00:00 UTC is an absolute moment, independent of timezone. Using UTC ensures that everyone, anywhere, gets the same result. This tool always works in UTC; you can manually add your timezone offset if needed.

🔹 Year 2038 problem

32‑bit systems store timestamps as signed 32‑bit integers, maxing out at 2038-01-19 03:14:07 UTC. 64‑bit systems have no such limit. This converter supports 64‑bit timestamps.

❓ Frequently Asked Questions

❓ Q1: Why is the converted time 8 hours behind my local time?

Because this tool uses pure UTC. For example, timestamp 1700000000 converts to 2023-11-15 06:13:20 UTC. If you are in Beijing (UTC+8), the local time is 2023-11-15 14:13:20. Just add your offset mentally, or use a timezone converter.

❓ Q2: How do I convert a 13‑digit millisecond timestamp to seconds?

Two ways: 1) Enter the 13‑digit number – the tool will recognise it as milliseconds and show both second and millisecond results; 2) Divide by 1000: e.g., Math.floor(1700000000000 / 1000) = 1700000000. Our result area always shows both formats.

❓ Q3: Does it support negative timestamps (before 1970)?

Yes. JavaScript's Date object handles negative timestamps, representing dates before 1970. For example, -1000000000 converts to 1968-04-28 15:33:20 UTC.

❓ Q4: What is ISO 8601 format?

ISO 8601 is the international date/time representation, e.g., 2023-11-15T06:13:20Z (the Z indicates UTC). This tool outputs in the more human‑friendly YYYY-MM-DD HH:mm:ss UTC format, which you can copy directly.

❓ Q5: Is my data sent to any server?

Absolutely not. This is a static HTML page – all conversion logic runs in your browser's JavaScript engine. You can even go offline and it still works. Your logs, timestamps, and debugging info never leave your computer.

❓ Q6: Can I convert multiple timestamps at once?

Currently it's a single‑line converter. Batch conversion is planned for the future. For processing many timestamps, you can paste them one by one, or use command‑line tools like date -d @timestamp.

🔗 Recommended Tools

This timestamp converter is part of the ng.cc developer toolkit. You might also like:

JWT Decoder/Generator – Parse iat/exp timestamps inside JWT
JSON Formatter & Validator – Beautify and validate JSON
Diff Checker – Compare text/code side‑by‑side
Base & Byte Calculator – Base conversion / byte size
Base64 Encoder/Decoder – Text/image ↔ Base64

⚡ All conversions happen locally – your timestamps never leave your browser.

⏱️ Timestamp Converter