--- title: Unix Timestamp Converter - Epoch to Date & Back description: Free Unix timestamp converter. Turn epoch time into human-readable dates (UTC, local, ISO 8601) and dates back into timestamps — seconds and milliseconds auto-detected, with a live current-epoch clock. canonical: https://watchfor.io/unix-timestamp-converter --- [Back to all free tools](/free-tools) # Timestamp Converter Convert Unix timestamps to human-readable dates and back — seconds, milliseconds and microseconds auto-detected, shown in UTC, your local timezone and ISO 8601, with a live current-epoch clock and copy buttons everywhere. Free, instant, no signup. [How to use this tool](/blog/how-to-convert-a-unix-timestamp) Current Unix timestamp … Timestamp → date Now Date → timestamp (your local time) Pick a date and time to get its Unix timestamp in seconds and milliseconds. ## Timestamp formats at a glance Format Example Where you'll see it Unix seconds 1767225600 APIs, databases, most Unix tools Unix milliseconds 1767225600000 JavaScript Date.now(), Java, logs ISO 8601 / RFC 3339 2026-01-01T00:00:00Z JSON APIs, OpenAPI, sortable logs RFC 2822 Thu, 01 Jan 2026 00:00:00 +0000 Email headers, HTTP Date header Everything here runs in your browser — timestamps you paste are never sent anywhere. Working with response times instead? Try the [ping test](/ping-test) or the [uptime calculator](/uptime-calculator). ## Frequently asked questions What is a Unix timestamp? A Unix timestamp (also called epoch time or POSIX time) is the number of seconds elapsed since 00:00:00 UTC on January 1, 1970 — the "Unix epoch". It's the standard way computers store points in time because it's a single integer that's unambiguous across timezones: 1767225600 means exactly the same moment everywhere on Earth. Is my timestamp in seconds or milliseconds? Count the digits. Current dates are 10 digits in seconds (≈1.7 billion) and 13 digits in milliseconds. JavaScript's Date.now() and Java's System.currentTimeMillis() return milliseconds; most Unix tools, PHP's time() and Python's time.time() use seconds. Some systems go further: 16 digits are microseconds, 19 digits nanoseconds (Go's UnixNano). This converter auto-detects the unit from the digit count. What is the year 2038 problem? Systems that store Unix time as a signed 32-bit integer overflow on January 19, 2038 at 03:14:07 UTC (timestamp 2,147,483,647) — one second later the value wraps to a date in 1901. Modern 64-bit systems are unaffected (good until ~292 billion years), but embedded devices, old file formats and legacy databases with 32-bit time fields can still be bitten. Do Unix timestamps include leap seconds? No. Unix time pretends every day has exactly 86,400 seconds. When a leap second is inserted into UTC, Unix time either repeats a second or smears it across the day (Google and AWS smear). This means Unix time is not a true count of elapsed SI seconds — but for virtually all application purposes that's a feature, not a bug: the math stays simple. How do timezones relate to timestamps? They don't — and that's the point. A Unix timestamp is always UTC-based; timezones only appear when you format it for humans. The same 1767225600 renders as 00:00 in London and 02:00 in Vilnius. Store timestamps (or ISO 8601 with offset) in your database and convert to the user's timezone only at display time — most timezone bugs come from breaking this rule. Can a Unix timestamp be negative? Yes — negative values count backwards from the 1970 epoch. -86400 is December 31, 1969. Dates before 1970 are perfectly representable, which matters for birthdates and historical data. Some languages and databases handle negative epochs poorly though, so test before relying on it. What's the difference between ISO 8601 and RFC 3339? RFC 3339 is essentially a strict profile of ISO 8601 for internet timestamps: 2026-08-24T09:30:00Z or with an offset like +02:00. ISO 8601 additionally allows week dates, ordinal dates, and omitting parts. For APIs, emit RFC 3339 with an explicit offset (or Z for UTC) — it sorts lexicographically and every language parses it. ## Timestamps decoded — now decode your downtime Every incident timeline starts with "when exactly did it break?". WatchFor records every check with precise timestamps, alerts you within seconds and gives you the full timeline from multiple regions. [Start monitoring for free](/pricing) Free plan · 15 monitors · no credit card required --- Canonical page: https://watchfor.io/unix-timestamp-converter · Site guide: https://watchfor.io/llms.txt