Unix Timestamp Converter (Epoch Time)
Convert Unix timestamps to readable dates — or dates to timestamps. Seconds and milliseconds are auto-detected, and results show both your local time and UTC, the two views every developer needs side by side.
How to use this calculator
- Choose the direction: decode a timestamp, or encode a date & time.
- Paste the timestamp (seconds or milliseconds both work) — or pick the date and local time.
- Press Convert to get local time, UTC, both timestamp formats and the ISO 8601 string.
Formula used
The "epoch" ignores leap seconds and is time-zone-free — the same instant has one timestamp everywhere on Earth. Milliseconds versions (used by JavaScript and Java) are simply ×1000; the converter auto-detects by magnitude.
Example calculation
1784980800 decodes to 25 July 2026, 12:00:00 UTC.
Round numbers are developer folklore: 1700000000 fell on 14 November 2023, and 2000000000 arrives on 18 May 2033. The famous 32-bit overflow ("Y2038") hits at 2147483647 — 19 January 2038.
What Unix time is
Unix time counts seconds from a fixed instant — midnight UTC, 1 January 1970 — giving every moment a single unambiguous integer. Databases, logs, APIs and operating systems use it because integers sort, subtract and compare trivially, with no time zones or formats to parse.
The costs are human-side: a timestamp is unreadable without conversion, and the seconds-vs-milliseconds ambiguity causes real bugs (a milliseconds value read as seconds lands you in the year 56,000-something). Length is the tell: 10 digits = seconds, 13 = milliseconds — exactly the auto-detection this tool applies.
Why use this calculator?
- Decode timestamps from logs, APIs and databases into dates you can reason about.
- Get seconds, milliseconds and ISO 8601 at once — whichever your code needs.
- See local and UTC together, the comparison that catches most timestamp bugs.
Frequently asked questions
How do I tell seconds from milliseconds timestamps?
Count digits: current Unix time in seconds is 10 digits (~1.75 billion); in milliseconds it's 13 digits. This converter auto-detects — anything ≥ 10¹² is treated as milliseconds.
What is the Year 2038 problem?
Systems storing Unix time as a signed 32-bit integer overflow at 2,147,483,647 seconds — 19 January 2038, 03:14:07 UTC. Modern 64-bit systems are safe for ~292 billion years, but embedded and legacy systems still need auditing.
Do Unix timestamps change with time zones?
No — a timestamp identifies one instant globally. Time zones only affect how that instant is displayed, which is why the converter shows both your local rendering and UTC.