Unix Timestamp Converter
Convert epoch time to a date and back — seconds, millis, micros & nanos
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Time zones are the hard part
Unit auto-detection
Seconds, milliseconds, microseconds, and nanoseconds are detected automatically from the digit count, so a 10-digit epoch, 13-digit millis, and 19-digit nanos each resolve without touching the unit dropdown.
Four formats at once
One input produces local time, UTC, ISO 8601, and a relative reading like three days ago, while the header clock ticks live seconds and milliseconds — click either to drop it into the converter.
Dates back to epoch
The reverse direction converts a chosen date into epoch seconds, milliseconds, and the ISO string, so an API expecting either precision gets its value from the same form.
✦ What Is a Unix Timestamp Converter?
A Unix timestamp counts time since the start of 1970 in UTC, and this converter works both directions through plain epoch-millisecond math. The top card is a live clock ticking every second in both seconds and milliseconds, either of which can be clicked straight into the input. Paste a value and the unit selector auto-detects seconds, milliseconds, microseconds or nanoseconds from digit length, then renders local time, UTC, ISO 8601 and a relative phrase, while the date picker runs the reverse trip back to epoch values.
Reading logs and minting epoch values
- Drop a log timestamp in to learn instantly whether it means last Tuesday or next year, with the local rendering, the UTC string and the ISO form side by side plus a relative reading such as days ago for quick triage.
- Seed the date picker, which starts prefilled with right now down to the second, pick any moment and copy out floor seconds, exact milliseconds or the ISO string for API payloads and database seeds.
Digit lengths, far futures and local zones
- Auto-detection keys off digit count, up to eleven digits reads as seconds, up to fourteen as milliseconds, up to seventeen as microseconds and beyond as nanoseconds, and choosing the unit by hand sticks until you refocus the input.
- Non-numeric or out-of-range input reads invalid rather than wrapping to 1970, seconds output is floored, and the date picker is interpreted in your own local zone, so the same wall-clock reads differently across time zones by design.
All math executes in your browser with no API calls and no tracking, so event logs stay confidential. Your timestamps are converted on-device and never uploaded anywhere.
Last updated · 2026-09-01
Epoch numbers versus ISO strings
Unix time counts seconds since 1970-01-01 UTC — deliberately zone-less. Everything zone-shaped happens when you render it:
- A bare number has no offset; the same 1700000000 is dinner in Berlin and lunch in New York.
- ISO 8601 strings carry their offset (Z or +08:00) — prefer them for storage, convert only for display.
- 10 digits = seconds, 13 digits = milliseconds: this tool auto-detects and says which it assumed.
Frequently asked questions
What is a Unix timestamp?⌄
It is the number of seconds (or milliseconds, microseconds, nanoseconds) elapsed since 00:00:00 UTC on 1 January 1970, the Unix epoch. It is timezone-independent, which makes it a compact, unambiguous way to store a moment in time.
How do you detect seconds vs milliseconds?⌄
By the number of digits: a 10-digit value is seconds, 13 digits is milliseconds, 16 is microseconds and 19 is nanoseconds. Automatic detection covers dates from 2001 to 2286; you can override the unit with the selector if your value falls outside that range.
Which timezone are the results in?⌄
The “Local” row uses your device timezone and locale via the Intl API; “UTC” and “ISO 8601” are always in UTC. The date-to-timestamp field interprets the date you pick in your local timezone.
Why does my timestamp shift by exactly one hour?⌄
Almost always a daylight-saving boundary. A wall-clock string like 2026-03-29 02:30 simply did not exist in Europe that year; parsers either jump forward an hour or pick a side depending on settings. Store UTC or full ISO offsets and the ambiguity disappears.