BrowserTools

Unix Timestamp Converter

Epoch to date and back, in your timezone

By Guga — BrowserTools maintainer, Tbilisi, Georgia Updated 2026-09-21
Free Private No uploads
What is Unix Timestamp Converter?

A Unix timestamp counts seconds since midnight UTC on the first of January 1970, with nothing before that point expressible as a positive number. That single convention explains most of the confusion around it: the value carries no timezone, no calendar and no daylight saving information, all of which the tool supplies by rendering the same instant several ways. Enter an epoch value and you get your local time, the UTC equivalent, full ISO 8601, the bare date, the bare time, and how far away it is in relative terms. The second panel works the other way, taking a date and time from your device's own clock and producing seconds, milliseconds and UTC. Both panels open on the current moment, so you can see immediately how the two representations line up.

Convert Unix timestamps to human-readable dates and times — or convert any date back to an epoch value in seconds or milliseconds. Supports local time and UTC side by side.

Private Unix Timestamp Converter In Your Browser

Unix Timestamp Converter is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.

Step-by-Step

How to use Unix Timestamp Converter

1

Type an epoch value into the Unix timestamp field, or tick milliseconds if that is the unit you have.

2

Read the six formatted lines below: local, UTC, ISO 8601, date, time and relative.

3

For the opposite direction, set the date and time in the second panel, which uses your machine's timezone.

4

Copy the Seconds or Millis line you need from the result below that panel.

Key Capabilities
  • One instant rendered six ways: local, UTC, ISO 8601, date, time and relative
  • A seconds or milliseconds toggle for reading the input in either unit
  • Reverse panel converting a local date and time into epoch seconds and milliseconds
  • Both panels initialised to the current moment for immediate comparison
Common Use Cases
  • A developer reading an epoch value out of an API response and needing to know what day it represents.
  • An analyst converting a column of Unix timestamps in a spreadsheet into readable dates for a report.
  • A student checking whether a timestamp is in seconds or milliseconds by seeing which interpretation gives a sensible date.
Clear Answers

Frequently Asked Questions

How do I tell seconds from milliseconds?
By the size of the number and by what date comes out. A ten-digit value is almost certainly seconds and gives a date around 2001 or later; a thirteen-digit value is milliseconds. Tick the milliseconds box and check which one produces a plausible date — if the seconds reading lands in 1970 and the milliseconds reading lands in 2020, you had milliseconds.
Why will it not accept a negative timestamp?
Only digits are accepted, so anything before 1970 is rejected. Negative epochs do exist and are valid — they are used to represent instants before the epoch — but the field is restricted to unsigned integers. For a pre-1970 date, use the date panel instead and subtract 2 147 483 648 seconds from the result.
Which timezone does the date panel use?
Your own. The input is a local date-and-time control and is interpreted in the browser's timezone, which is why the same value produces different epoch numbers on two machines in different places. If you have a UTC string in hand, convert it in the upper panel and read the UTC line, which is unambiguous.
What is the relative line actually measuring?
The gap between that instant and now, phrased as minutes, hours or days depending on magnitude. It recalculates when the page loads, so a token or timestamp that was fresh an hour ago will start saying an hour ago. It is a convenience for reading logs, not a precise clock.