Convert Unix timestamps to dates and vice versa
Built & maintained by Pappu Venkata Subbi Reddy, founder of Clacify
Timestamp Converter translates between Unix timestamps (the number of seconds since 1 January 1970) and human-readable dates, in both directions, instantly. Paste a timestamp to see the date and time it represents, or pick a date to get its timestamp — plus a one-click "now" button that gives you the current timestamp for testing. It also shows relative time ("3 hours ago," "in 2 days"), which is useful for sanity-checking whether a timestamp your code just generated actually points to the moment you expected. Every programming language and database eventually needs to convert between these two representations, and doing it by hand or in a REPL is slower than pasting the number here.
A Unix timestamp counts seconds elapsed since the "Unix epoch" — 00:00:00 UTC on 1 January 1970 — chosen as a reference point decades ago and now the near-universal standard for representing a moment in time as a single number, independent of timezone or calendar formatting. Converting timestamp-to-date multiplies the value by 1000 (since JavaScript's Date object works in milliseconds, not seconds) and constructs a native Date object from it, which the browser then renders in your local timezone. Converting date-to-timestamp does the reverse: parsing the date input into a Date object, calling getTime() to get milliseconds since the epoch, then dividing by 1000. Relative time is computed by subtracting the current timestamp from the target and expressing the difference in the largest sensible unit (seconds, minutes, hours, or days).
Storing "3:45 PM on 24 August" directly is ambiguous the moment more than one timezone is involved — is that IST, UTC, or the server's local time? A Unix timestamp sidesteps the whole problem: it's a single number, unambiguous everywhere on Earth, and every language converts it to its own local display format only at the point of showing it to a user. This is why timestamps are the standard way databases, APIs, and log files record "when" — the ambiguity gets resolved once, at render time, rather than needing to be tracked through every system a piece of data passes through.
The single most common timestamp bug is mixing up units: Unix timestamps are traditionally in seconds, but JavaScript's own Date.now() and getTime() return milliseconds — a 1000× difference that, if missed, either produces a date in 1970 (a seconds-value treated as milliseconds, so it barely moves past the epoch) or a nonsensical date thousands of years in the future (a milliseconds-value treated as seconds). A quick sanity check: a current-day timestamp in seconds is a 10-digit number; in milliseconds, it's 13 digits. This tool accepts either and converts correctly, but knowing the digit-count tell is worth remembering for reading raw values in logs or database rows.
A Unix timestamp (or epoch time) is the number of seconds elapsed since 1 January 1970 00:00:00 UTC (the Unix Epoch). It is a timezone-independent way to represent any moment in time as a single integer. For example, the timestamp 1700000000 equals 14 November 2023 22:13:20 UTC.
Enter the Unix timestamp into Clacify's Timestamp Converter and it instantly shows the corresponding date and time in your local timezone and UTC. The tool auto-detects whether you've entered seconds or milliseconds (JavaScript's Date.now()) based on the number of digits — no manual toggle needed.