Unix timestamp converter with a clock-time mode attached
A cron log says the job wrote its file at 1699999200, and you sit in Berlin wondering whether that was before midnight. Paste the number into this Unix timestamp converter and read the local time, UTC and ISO 8601. Two more tabs convert a clock time between time zones and show a world clock table.
Ten digits, thirteen digits and the year 55000
JavaScript's Date.now() returns 13 digits, PHP's time() returns 10. Mix them up and you get a date in 1970 or in the year 55000. The tool accepts both and guesses the unit from the length. Up to 11 characters count as seconds, longer values as milliseconds.
The rule counts characters and nothing else. A leading minus sign is not counted, so -1000000000 is read as seconds. A value with decimals such as 1700000000.5 has 12 characters, so it is read as milliseconds and lands in January 1970. Remove the decimals first.
Reading a date from the number, and the number from a date
- Open the first tab. Type or paste the number into Timestamp (seconds or milliseconds).
- Read the results on the right: local time, UTC, ISO 8601, both timestamp units, the RFC 2822 / HTTP header format, the relative age and the calendar week. The copy button next to a row copies that value.
- To go the other way, choose a date in the date picker and set the input time zone. The timestamp field follows.
- Shift the time with -1 day, -1 hr, +1 hr and +1 day. Use current time resets everything to now.
- For a time zone question, open Time Zone Converter, enter the source time, pick source and target zone, and press the swap arrow to reverse them.
Los Angeles at 17:00 is already tomorrow in Berlin
A call at 17:00 in Los Angeles is 02:00 the next day in Berlin. The converter shows the hour difference, a "+1 day (tomorrow)" marker and the UTC offset of the target zone, so you do not have to count.
The dropdown lists 31 common zones first. All other IANA zones appear only when your browser supports Intl.supportedValuesOf. A local time that does not exist (the hour skipped in spring) or occurs twice (autumn) gets one result without a warning. The world clock table shows a fixed list of 15 cities.
Where the buttons use your own time zone
The buttons 00:00 and 23:59 use your browser's time zone, even when another input time zone is selected. The calendar week and the day of the year follow the same rule. The relative age counts in days at most, so an old date reads "1200 days ago", not "3 years ago".
The seconds output is rounded down, and the date picker shows whole seconds only. Dates beyond the range of the JavaScript Date object, about 270,000 years either side of 1970, show as invalid.
What the page sends, which is nothing
All calculation runs in your browser with the JavaScript Date and Intl APIs. Typing or pressing a button sends no request, and the network panel of your developer tools shows this. The live clock at the top ticks locally once per second. The copy buttons write to your clipboard and nowhere else.