Unix Timestamp Converter
Convert between Unix time and readable dates in UTC or local time.
Paste a timestamp or an ISO date on the left.
How it works
A Unix timestamp is a count since midnight UTC on 1 January 1970. The count is unambiguous. The unit is not, and that is where epoch converters go wrong.
The unit is decided by digit count
1758240000 and 1758240000000 are the same instant in different units. The usual fix is
to check whether the result lands somewhere plausible, which quietly breaks on real data: 86400 is 2
January 1970 in seconds, and a rule demanding a modern date reads it as milliseconds and reports 00:01:26 on 1
January instead. Digit count is a property of what you pasted rather than of when the page loaded, so the same
string always converts the same way — and the tool names the unit it picked.
Microseconds and nanoseconds arrive already broken
A 19-digit nanosecond timestamp is larger than a JavaScript number holds exactly. Reading it as a number and then dividing loses the precision the division was supposed to preserve, so the scaling happens in integer arithmetic first and only becomes a number once it is small enough to be one.
Ambiguous dates are refused, not guessed
Going the other way, only ISO 8601 is accepted. 03/04/2026 is March in one country and April in
another, and a converter that picks has made a claim about your data rather than read it. A date with no offset is
read as UTC and labelled as such.
Example
1758240000 is 10 digits, so it is seconds: Friday, 19 September 2026 at 00:00:00 UTC. Paste
2026-02-30 and it is refused rather than silently moved to 2 March, which is what a browser's own
date parser does with it.
Frequently asked questions
How does it know whether my number is seconds or milliseconds?
By digit count, not by how close the result lands to today. A range check would reclassify real timestamps: 86400 is 2 January 1970 in seconds, and a rule demanding a plausible modern date would call it milliseconds and render it as 00:01:26 on 1 January. Digit count is a property of what you pasted, so the same string always reads the same way. The tool states which unit it chose and why.
Does it handle microseconds and nanoseconds?
Yes. Database and tracing systems emit both, and a 19-digit nanosecond timestamp is larger than a JavaScript number can hold exactly — so the conversion is done in integer arithmetic before it becomes a number, rather than after, when the precision would already be gone.
Which timezone does it use?
UTC is the primary output, with your local time shown alongside and labelled. A Unix timestamp carries no timezone, so UTC is the only rendering that means the same thing on every machine — which is why logs and APIs use it.
Why was my date rejected as not real?
Because the browser would otherwise have accepted it and moved it. Date parsing rolls an out-of-range day over silently, so 2026-02-30 becomes 2 March without complaint. The tool reads the instant back and compares it to what you wrote, and refuses rather than shifting your date by two days.
What is the ISO week for?
Incident timelines and reporting periods are usually indexed by it, and it does not always agree with the calendar year: 30 December 2024 falls in week 1 of 2025, because the week containing that Thursday belongs to the following year.
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