Unix Time Converter
Convert Unix epoch time and see the same instant across several timezones, with calendar details and simple arithmetic.
Your data stays on your device
The unit is detected from the magnitude: 10 digits is seconds, 13 is milliseconds.
About this tool
Unix time counts seconds since 1 January 1970 UTC, ignoring leap seconds. Its appeal is that an instant is a single integer with no timezone, no format and no ambiguity — the complexity only appears when you convert it back for a human.
This page focuses on that conversion. It shows one instant across multiple timezones side by side, adds calendar details such as ISO week number and day of year, and lets you shift the value by an interval to answer questions like "what is the timestamp seven days from now".
How to use this tool
- Enter a Unix timestamp in seconds, or press "now".
- Review the same instant rendered in UTC, your local zone and the additional zones you select.
- Use the offset controls to add or subtract days, hours or minutes.
- Copy whichever representation you need.
Key features
- One instant compared across several timezones simultaneously
- Day of week, day of year and ISO week number
- Interval arithmetic in days, hours, minutes and seconds
- Seconds and milliseconds shown together
- Leap year indicator for the resulting date
- Copy any individual representation
Example
Input — Unix time
1767225600Output — Date
UTC 2026-01-01 00:00:00
Asia/Seoul 2026-01-01 09:00:00
America/NY 2025-12-31 19:00:00
ISO week 1 · day 1 of 2026Good to know
- Timezone rendering relies on the browser Intl database; historical rule changes may differ from your server.
- Leap seconds are not modelled, matching the Unix time definition.
- Very large values beyond the year 275760 exceed the JavaScript Date range and are rejected.
Frequently asked questions
What is the year 2038 problem?
A signed 32-bit Unix timestamp overflows on 19 January 2038. Modern systems use 64-bit values, but legacy code and some embedded devices remain affected.
Does Unix time include leap seconds?
No. It assumes every day is exactly 86,400 seconds, which is why it stays simple at the cost of not being a true count of elapsed physical seconds.
Why compare multiple timezones?
Because incident timelines and scheduled jobs frequently span regions. Seeing the same instant in each zone removes a common source of error.
Are negative timestamps valid?
Yes, they represent dates before 1970. They are supported here, though some databases and languages handle them inconsistently.
Your data stays on your device
Your data is processed locally in your browser and is not uploaded to our server. This page keeps working after you go offline, because there is nothing to send.