Free Online Unix Timestamp Converter
Convert Unix timestamps (epoch time) to human-readable dates and back, instantly. Auto-detects seconds vs milliseconds. 100% in your browser, nothing uploaded.
What Is a Unix Timestamp?
A Unix timestamp (also called "epoch time") counts the seconds that have elapsed since January 1, 1970 00:00:00 UTC — a fixed reference point known as "the epoch." Instead of storing a date as a string like "2026-09-02 14:30:00", which varies by locale, timezone, and format, computers store it as a single integer. That makes date math trivial: comparing two points in time, sorting records chronologically, or calculating a duration is just subtraction, with no string parsing required. This is why timestamps show up everywhere under the hood — database created_at columns, API responses, log files, JWT expiry fields, and file metadata all commonly use epoch time internally, even when the UI displays a friendly formatted date.
Seconds vs Milliseconds: Telling Timestamps Apart
The single most common mix-up with Unix timestamps is unit confusion. For any date in the present era, a rule of thumb works reliably: a 10-digit number (e.g. 1735689600) is almost always seconds, while a 13-digit number (e.g. 1735689600000) is almost always milliseconds. This tool auto-detects which one you've pasted based on digit count, so you don't need to convert manually. The split exists because different ecosystems standardized on different units: JavaScript's Date.now() returns milliseconds, while most traditional Unix/Linux tools, Python's time.time()-derived conventions in scripting, and classic API designs use whole seconds. Getting this wrong is a classic bug — feeding a millisecond value into a function expecting seconds lands you on a date around the year 1970, and vice versa produces a date far in the future.
Unix 时间戳转换工具
这是一个免费的在线 Unix 时间戳（epoch 时间）转换工具，可将时间戳转换为可读日期，也可将日期转换为时间戳，自动识别秒和毫秒格式。所有计算均在浏览器本地完成，无需上传数据，保护隐私，适合开发者调试 API、日志和数据库时间字段使用。