Unix Timestamp (Seconds) Converter

A Unix timestamp in seconds is the single most common way computers store a point in time: it is the count of seconds since the Unix epoch, 1970-01-01T00:00:00Z. Because it is just an integer and is independent of timezone, it is used everywhere from database columns to JWT exp claims to log files. This converter turns those bare numbers into readable dates and back again, entirely in your browser.

How it works

To decode epoch seconds, the tool multiplies the value by 1000 (JavaScript’s Date works in milliseconds) and builds a Date object:

const date = new Date(epochSeconds * 1000);
date.toISOString(); // UTC ISO-8601

To encode a date-time back to seconds, it parses the date string into a Date, takes getTime() (milliseconds), and divides by 1000, flooring to a whole second.

A present-day seconds timestamp is about 10 digits (for example 1700000000 is in November 2023). If your number is ~13 digits it is almost certainly in milliseconds — use the milliseconds converter instead, or the date will be wrong by roughly fifty years.

Tips and notes

• Negative timestamps are valid and represent dates before 1970.
• Leap seconds are not represented in Unix time, so the count is a smooth seconds-since-epoch value.
• The “local” output reflects your browser’s timezone; the UTC output is canonical and is what you should store or transmit.