Unix Timestamp Converter (Epoch ⇄ Date & Time)
Convert epoch timestamps in seconds or milliseconds to UTC, ISO, and local time — and turn any date and time back into Unix seconds, with a live ticking now.
Unix Timestamp — interactive calculator, computed instantly in your browser.
Unix Epoch Time Explained: Seconds, Milliseconds, and Conversions
1970-01-01 UTC = 0 · every second since is just a bigger integer
Digit count tells seconds from milliseconds: 10 digits is seconds, 13 digits is JavaScript time
Unix time counts the seconds elapsed since midnight UTC on January 1, 1970 — the epoch every mainstream system agreed to call zero. It is timezone-free, sortable, and compact, which is why logs, databases, JWTs, and APIs all speak it. This converter runs both directions live: epoch to readable date in UTC and your local timezone, and any date back to epoch, with a ticking now counter.
1. Reading a Timestamp
- Ten-digit values are seconds — current timestamps hover in the 1.7–1.8 billion range
- Thirteen-digit values are milliseconds, the native unit of JavaScript Date.now()
- The UTC card is identical for everyone on Earth; only the local card changes with your timezone
- Pair foreign offsets with the 🌍 Time Zone Converter before calendaring anything
2. Building a Timestamp from a Date
- The datetime field converts to your local epoch instantly — no timezone math needed by hand
- Midnight presets matter: many systems reset counters at 00:00 local or 00:00 UTC, not both
- Day-level arithmetic belongs with the 📅 Date Calculator — epoch handles instants, calendars handle spans
- Leap seconds are smeared by most systems, so every UTC day holds exactly 86,400 counted seconds
3. Landmark Values Worth Knowing
- 0 is 1970-01-01; 946684800 is Y2K; 1000000000 landed on 2001-09-09
- JavaScript's 32-bit trap: some legacy code stores seconds, overflowing around 2038 — the classic Year 2038 problem on 32-bit systems
- Milliseconds overflow nothing practical until far future dates — the format modern JavaScript prefers
- Negative values reach before the epoch — 1969 and earlier, if a system allows them
4. Where You Will Meet Epoch Time
Database created_at columns, HTTP Last-Modified headers, log lines, cryptocurrency block times, and JWT expiration claims all carry epoch integers. Convert before debugging a date that looks decades off — the seconds-versus-millisecond mix-up accounts for most of them. For human-facing spans between two moments rather than the moments themselves, use the ⏱ Time Duration Calculator instead.
🔗 Time Systems & Timestamps
Logs, databases, and APIs speak in epoch integers — one timezone-free number every system agrees on. Convert alongside the 🗓 Date & Time Hub with the 📅 Date Calculator for calendar-day math.
When an epoch lands in a foreign timezone, pair it with the 🌍 Time Zone Converter before scheduling anything.
Frequently Asked Questions (Unix Timestamp)
If it is seconds, multiply by 1000 and read the result as milliseconds; if it already has 13 digits, read it directly. This calculator does the detection automatically and prints UTC, your local time, ISO style, and a relative label like 3 hours ago.
By digit count: current second timestamps are ten digits (about 1.7 billion), while JavaScript millisecond values are thirteen digits (about 1.7 trillion). The unit card here reports which interpretation was applied.
A value near zero means the seconds value was read as milliseconds — or the original value was never set (null defaults to zero in many systems). Zero itself is exactly January 1, 1970 UTC, the epoch origin.
The live card at the top of this page shows the current epoch in seconds and milliseconds, updating every second. The Now chip also fills the conversion field so you can inspect the full UTC and local breakdown.