Timestamp Converter
A Unix timestamp (also called epoch time) is the number of seconds — or, increasingly, milliseconds — since January 1, 1970, 00:00:00 UTC. Databases, APIs and logging systems frequently store moments in time this way, which is convenient for machines but unreadable for humans. This tool converts a timestamp into a readable date in both UTC and your own local timezone, and vice versa: enter a date and time and get the corresponding timestamp in both seconds and milliseconds instantly. When converting a timestamp to a date, the tool automatically detects whether you entered a seconds- or milliseconds-based timestamp, based on the number of digits. Everything happens entirely locally in your browser using JavaScript's built-in Date API — nothing is sent to our server.
What people use this for
1700000000 (seconds) → 14-11-2023 22:13:20 UTC1700000000000 (milliseconds) → 14-11-2023 22:13:20 UTC0 (seconds) → 01-01-1970 00:00:00 UTC — the start of the Unix epoch
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What is a Unix timestamp?
A Unix timestamp is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC — the so-called 'Unix epoch'. It's a compact, timezone-independent way to record an exact moment in time as a single number, which is why it's widely used in databases, APIs, log files and configuration files.
What's the difference between seconds and milliseconds, and why does this cause so many bugs?
Some systems store a timestamp in whole seconds (for example most Unix/Linux tools and many database columns), others in milliseconds (for example JavaScript's Date.now() and the majority of modern JSON APIs). That difference is exactly a factor of 1000, and it's one of the most common sources of date-related bugs: feed a seconds timestamp to a function that expects milliseconds (or vice versa) and you won't get an error — you'll get a date that's off by a factor of a thousand, often landing somewhere around January 1, 1970 or far in the future. This tool automatically detects which unit you entered based on the digit count, precisely to prevent this kind of confusion — but when in doubt, always check the documentation of the system the timestamp came from.
How does the tool decide whether I entered seconds or milliseconds?
Based on the number of digits: a timestamp of 10 digits or fewer is interpreted as seconds (covering every date between 1970 and the year 2286), one of 11 digits or more as milliseconds. Current seconds timestamps have 10 digits and current milliseconds timestamps have 13, so in practice this detection is unambiguous. The detected unit is always displayed next to the input field so you can double-check it.
Why does the tool show both UTC and my local time?
The exact same moment in time corresponds to a different clock time depending on the timezone you're looking from — 14:00 UTC, for example, is 15:00 or 16:00 in the Netherlands depending on standard or daylight saving time. Showing both lets you see, at a glance, the timezone-independent reference value (UTC, often what servers and APIs log) alongside the time as it would actually appear on your own clock. Your local timezone is read automatically from your browser; nothing is sent to any server.