Auto-detects the unit
A ten-digit value is seconds, thirteen is milliseconds, sixteen is microseconds. No manual selection and no silently-wrong results from a unit mismatch.
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Unix Timestamp Converter
Convert Unix timestamps to readable dates and back, in any timezone.
- Input
- No upload needed — instant
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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Overview
About the Unix Timestamp Converter
Convert Unix timestamps to human-readable dates free. Handles seconds and milliseconds, UTC and local time, ISO 8601, and relative time — with a live clock.
Unix time is the closest thing computing has to a universal clock: one integer, no timezone, no calendar irregularities, trivially comparable and sortable. That simplicity is why it is stored in databases, sent in API responses and written into log lines everywhere — and why reading it requires a converter.
The epoch and the count
Everything is measured from 00:00:00 UTC on 1 January 1970. Timestamps before that moment are negative. The count excludes leap seconds, so a day is always exactly 86400 units regardless of what the International Earth Rotation Service has done to the actual calendar.
Units, and the bug they cause
JavaScript's Date.now() returns milliseconds. Most Unix shells and Python's time.time() return seconds. Go's time.Now().Unix() returns seconds while UnixNano() returns nanoseconds. Mixing these up is one of the most frequent bugs in cross-language systems, and it fails quietly: a millisecond value read as seconds does not error, it just reports the year 57,000.
Timezone is a display concern
A timestamp has no timezone. It denotes one instant, and every timezone renders that instant with a different wall-clock reading. The habit that prevents most confusion: always look at the UTC rendering first, establish the true instant, then consider the local rendering as a presentation of it.
This tool shows both simultaneously for exactly that reason.
ISO 8601 and why the Z matters
2026-03-14T22:13:20Z — the trailing Z (Zulu) means UTC. Without it, or with an offset like +05:30, the string means something different. Omitting the timezone designator from an ISO timestamp is a genuine interoperability bug: the receiver has to guess whether you meant UTC or their local time.
Common debugging patterns
- Date is exactly 1 January 1970. A zero or null timestamp, or a milliseconds value treated as seconds and truncated.
- Date is far in the future. A millisecond or microsecond value interpreted as seconds.
- Date is off by a round number of hours. Timezone rendering, not a data problem.
- Date is off by a few seconds inconsistently. Possibly leap seconds in a system that accounts for them, or clock drift between hosts.
- Date flips to 1901 or 2038. 32-bit signed overflow.
Step by step
How to use the Unix Timestamp Converter
Paste a Unix timestamp — the tool detects seconds versus milliseconds automatically.
Read the result in UTC and in your local timezone simultaneously.
Or enter a date and time to convert the other way, into a timestamp.
Copy any of the output formats: ISO 8601, RFC 2822, SQL DATETIME or relative time.
Use the now button to grab the current timestamp at any moment.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
UTC and local side by side
The single most common timestamp bug is confusing the two. Showing both eliminates the ambiguity rather than asking you to remember which one you set.
Every format you need to paste
ISO 8601 for APIs, RFC 2822 for email headers, SQL DATETIME for queries, and a relative form for UI copy — all from one conversion.
Bidirectional
Convert a timestamp to a date or a date to a timestamp in the same interface, which is what debugging actually requires.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
What is a Unix timestamp?
The number of seconds elapsed since 00:00:00 UTC on 1 January 1970, the Unix epoch, excluding leap seconds. It is a single integer that represents an absolute instant identically on every system, which is why it is the standard interchange format.
How do I know if a timestamp is in seconds or milliseconds?
Count the digits. Ten digits is seconds — the current value is around 1.78 billion. Thirteen is milliseconds, sixteen is microseconds and nineteen is nanoseconds. A seconds value interpreted as milliseconds lands in January 1970; a milliseconds value interpreted as seconds lands around the year 57,000.
Why does my timestamp show a different date than expected?
Almost always a timezone confusion. The timestamp itself is timezone-neutral; the date you see depends on the zone it is rendered in. 1700000000 is 2023-11-14 22:13:20 UTC but 2023-11-15 in Tokyo. Check the UTC value first, then work out the offset.
What is the Year 2038 problem?
A signed 32-bit integer counting seconds overflows at 03:14:07 UTC on 19 January 2038, wrapping to a large negative number and appearing as 1901. Systems storing timestamps in a 32-bit int need migration to 64-bit, which pushes the limit to about 292 billion years.
Are leap seconds included?
No. Unix time deliberately ignores leap seconds, treating every day as exactly 86400 seconds. This means a Unix timestamp is not exactly the number of real elapsed seconds since 1970 — it is off by the 27 leap seconds inserted so far. For most purposes this is irrelevant; for precise interval measurement, use a monotonic clock.