It's 2:15 AM. You're staring at a database log full of numeric timestamps like 1635724800. You need to correlate them with user activity reports that use human-readable dates. You grab a calculator and start dividing by 86400 (seconds in a day) to estimate the date. After 20 minutes of manual arithmetic, you're off by two days because you forgot to account for leap years.
I've been there. Anyone who's worked with APIs, databases, or system logs knows the pain of dealing with Unix timestamps. They're compact, machine-friendly, and universal — but they're utterly unreadable to humans.
That frustration led me to build a proper timestamp converter — the kind I wish I'd had that night.
What it does:
Bidirectional conversion — timestamp → date and date → timestamp
Multiple precisions — seconds (Unix standard) and milliseconds (common in JavaScript and many APIs)
Timezone support — switch between UTC and your local timezone instantly
Batch mode — convert multiple timestamps at once with CSV export
100% browser-based — your data never leaves your machine
Under the hood, the converter first determines if the unit is seconds or milliseconds. If milliseconds, it divides by 1000 to get seconds. Then, it calculates the number of days, hours, minutes, and seconds from the epoch offset, accounting for timezone offsets, daylight saving time, and leap years. It's the same logic used by professional date libraries — but accessible from your browser with zero setup.
In this guide, I break down how timestamp conversion works mechanically — from epoch arithmetic to calendrical calculations to timezone handling — so you understand exactly what's happening when you hit that Convert button.
Top comments (0)