Unix Timestamp Converter
Convert a Unix timestamp (seconds or milliseconds) to a human-readable UTC and local date and time, with relative time.
Result
- Interpreted asseconds
- ISO 8601 (UTC)2023-11-14T22:13:20.000Z
- UTCTue Nov 14, 2023 22:13:20 UTC
- Local (UTC+0)Tue Nov 14, 2023 22:13:20 (UTC+0)
- Seconds since epoch1700000000
- Milliseconds since epoch1700000000000
Step-by-step
- Input interpreted as seconds → 1700000000000 ms since 1970-01-01 UTC.
- UTC date = 2023-11-14T22:13:20.000Z.
- Apply offset UTC+0: Tue Nov 14, 2023 22:13:20 (UTC+0).
How to use this calculator
- Paste the Unix timestamp.
- Leave unit on auto-detect, or set seconds/milliseconds explicitly.
- Enter your UTC offset for a local-time display (0 for UTC).
- Read the ISO, UTC, and local date-time plus both epoch representations.
About this calculator
Unix time (or epoch time) is the number of seconds that have elapsed since midnight UTC on January 1, 1970, and it is how computers almost universally store moments in time. This converter turns a Unix timestamp into a readable date and time. It auto-detects whether your number is in seconds (10 digits for current dates) or milliseconds (13 digits, as JavaScript uses), or you can set the unit explicitly. It shows the result in ISO 8601 format, a full UTC string, and your local time using a UTC offset you provide, plus both the seconds and milliseconds representations for convenience. Unix timestamps are timezone-agnostic — they always refer to the same instant in UTC — which is why the local display requires you to specify your offset. This is handy for debugging logs, API responses, and database records that store epoch times.
How it works — the formula
ms = seconds × 1000
Date = 1970-01-01T00:00:00Z + ms
Local = UTC + offset hoursThe epoch plus the elapsed milliseconds gives the UTC instant; adding a fixed offset yields local time.
Worked examples
- Inputs:
- timestamp=1700000000, unit=auto
- Output:
- 2023-11-14T22:13:20Z
- Inputs:
- timestamp=1700000000000, unit=auto
- Output:
- same instant, detected as ms
- Inputs:
- timestamp=0
- Output:
- 1970-01-01T00:00:00Z (the epoch)
Limitations
- Local time uses a fixed offset; no automatic DST handling.
- Auto-detect threshold is 1e12 (≈ year 33658 in seconds).
- Bound by JavaScript’s Date range (±~273,790 years).
Conversions are exact UTC; local display depends on the offset you provide.