Timestamp Converter
Convert a Unix timestamp to a date, or a date to a timestamp — in UTC and your own zone.
Runs entirely in your browser
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How to use
- Choose whether you have a timestamp or a date.
- Paste it in — or press Use now for the current instant.
- Read the result in UTC and in your own time zone, which is named so there is no doubt.
- Copy whichever form you need.
Features
- Seconds and milliseconds, detected from the value or set explicitly.
- Every result shown in UTC and in your own zone, with the zone named and its offset.
- Dates before 1970 and far into the future, with a clear error past what a timestamp can hold.
- A bare date is read as UTC, not as local midnight — the classic off-by-one day.
- Runs entirely in your browser.
Frequently asked questions
- Is my timestamp in seconds or milliseconds?
- Ten digits is seconds; thirteen is milliseconds. A timestamp around 1.7 billion is seconds and lands in the 2020s; the same number read as milliseconds lands in 1970. You can also set the unit explicitly rather than rely on the guess.
- Why does my date come out a day earlier than I expected?
- Because a bare date like 2026-08-11 has no time zone, and this tool reads it as UTC midnight, which is what ISO 8601 says. If you are east of Greenwich, UTC midnight is still the previous evening where you are. Add an explicit zone — 2026-08-11T00:00:00+07:00 — when you mean midnight where you are.
- What is the largest timestamp this handles?
- About 8.64×10¹⁵ milliseconds either side of 1970 — roughly 273,790 years. That is the range a JavaScript date can represent; past it every calculation returns a non-number, so the tool says so instead of showing something plausible and wrong.
- Does it account for leap seconds?
- No, and neither does Unix time. A Unix timestamp counts as if every day were exactly 86,400 seconds long, so leap seconds are absorbed rather than counted. That is the definition, not a shortcut taken here.
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