What is a Unix timestamp (Epoch time)?
A Unix timestamp is an integer counting the number of seconds that have elapsed since **January 1, 1970, at 00:00:00 UTC** (the Unix Epoch), minus leap seconds. It is timezone-independent, making it the standard choice for computers to store and compare dates globally.
What is the "Year 2038" problem (Y2K38)?
On **January 19, 2038, at 03:14:07 UTC**, standard 32-bit signed integers will overflow, resetting to negative numbers (representing December 13, 1901). Modern databases and programming languages are migrating to 64-bit integers, which solves the problem for billions of years. SimplyUtils fully supports 64-bit timestamps to let you safely convert dates beyond 2038.
How do leap seconds affect Unix time?
Unix time does not account for leap seconds. When a leap second is added, the Unix timestamp simply repeats the last second of the day. Most modern cloud systems (like Google or AWS) use a technique called "leap smearing" to slowly skew clocks over a day to prevent duplicate timestamps.
Why does JavaScript display a 13-digit timestamp instead of a 10-digit one?
Standard Unix timestamps count time in seconds (10-digit). JavaScript's native Date.now() counts time in milliseconds (13-digit) to allow more granular client-side rendering. To convert milliseconds to seconds in JS, divide the value by 1,000 (e.g. Math.floor(Date.now() / 1000)).
Strict Local Renders: Because all rendering operations take place completely inside your local browser memory space, your images are never sent over the internet or stored on a server.