Unix Timestamp Converter

How to use it

1. 1Paste a timestamp, or a dateThe input is labelled for whichever direction you are converting: "Unix timestamp" going one way, "Date and time" going the other. Flipping the direction clears the box, because the old value never means the same thing. Everything happens inside your browser — nothing is uploaded, so there is nothing for us to store, log or lose.
2. 2Read the result as it updatesThere is no button to press. The conversion updates as you type, and "Right now" fills in the current moment if you just need that. The output recomputes every time you change the text or one of the options above it.
3. 3Set the direction with ConvertDetect automatically usually gets it right; timestamp → date and date → timestamp force it when your input is ambiguous.
4. 4Check the UnitSeconds or milliseconds. Getting this wrong lands you in 1970 or in the year 55000, which is at least an obvious kind of wrong — a ten-digit value is seconds and a thirteen-digit one is milliseconds.
5. 5Read both the UTC and local answersA timestamp is a moment; a date is a moment plus a place. "Interpret as" decides which timezone your input meant, and the result shows both so an off-by-a-few-hours mistake is visible.
6. 6Copy or download the resultThe buttons under the output put it on your clipboard or save it as a file, and each one says exactly what it will copy or download. Any note about something the tool changed or deliberately left alone is shown with the result rather than hidden.

About this tool

Unix time counts the seconds since 1 January 1970 UTC. It is how nearly every log, database and API stores an instant, because it is a single number with no time zone attached — and it is unreadable to a person, which is why this tool exists.

It converts in both directions and shows a live clock. It also refuses to guess quietly: where an answer depends on an assumption, the assumption is shown and can be changed.

Understanding the result

The same instant is shown as seconds, milliseconds, ISO 8601, UTC and your local time, with the day of the week and a plain-language "3 days ago" — which is usually the part you actually wanted.

When you do not specify the unit, it is inferred from the number of digits and the result says so. 1700000000 and 1700000000000 are the same instant in different units, and reading one as the other puts the date fifty years out.

Converting a date to a timestamp asks whether you mean local time or UTC, because the two give different numbers. A date that carries its own offset — a trailing Z or +05:30 — settles it, and the tool says the setting was not applied.

Example

1700000000

14 November 2023, 22:13:20 UTC
Tuesday
2023-11-14T22:13:20.000Z

Limitations

• Unix time does not count leap seconds. A timestamp cannot represent 23:59:60, and the second either side of one is not what an atomic clock would say.
• Dates must be written year-month-day. 08/04/2026 is refused rather than guessed at, because it means 4 August in Britain and 8 April in the United States.
• Time zone conversion uses your device's time zone database. If the device is wrong, or the zone's rules changed after the device was last updated, historic conversions can be off by an hour.
• Local times that fall in a daylight-saving gap do not exist. The tool reports what it read them as rather than silently answering a different question.
• The representable range is roughly 271821 BC to 275760 AD — a limit of the browser's date type, not of Unix time.

Questions