A timestamp generator writes Unix time: seconds or milliseconds since 1970-01-01T00:00:00Z. This timestamp generator can snapshot the current instant, convert a local date-time from this browser into Unix seconds, or convert Unix seconds into ISO 8601 UTC. Unix time is UTC. The local field uses the zone the browser already has. That is not a time-zone converter. It will not apply IANA zones or DST tables you type by name.
This is not the Date Difference Calculator and not the Time Duration Calculator. Those pages count spans. This page names an instant. It will not tell you how old someone is and will not wrap midnight for a shift length.
Use Now when you need a created_at value. Use From local time when you already have a civil clock in this zone. Use From Unix seconds when a log printed an integer and you want the UTC ISO form. Copy seconds writes the Unix seconds row.
Empty local time and empty Unix seconds are errors for those actions. Non-integer Unix seconds are rejected. Extremely large Unix values are refused so the Date object stays usable. Labels sit above the fields.
Unix seconds 0 is 1970-01-01T00:00:00.000Z. Unix seconds 1700000000 is 2023-11-14T22:13:20.000Z. Now uses this computer’s clock; two clicks a second apart differ by about one second. A local time of 2020-01-01 00:00 in a UTC+4 browser becomes 2019-12-31T20:00:00.000Z. Script-looking text in Unix seconds is rejected as not a number.
0 → 1970-01-01T00:00:00.000ZIf the job was “how many nights between two dates,” leave this page. If the job was “what is the Unix time of this instant,” stay. Write seconds or milliseconds next to the number. Mixing them is how a token expires in 1970 or in the year 56000.
The ISO row always includes milliseconds and a Z. Some APIs want seconds only as an integer. Copy seconds is for that case. Some APIs want milliseconds. Read the milliseconds row instead of multiplying in your head if you can avoid it.
The local field’s step is one second. Sub-second local input is not offered. Now still reports milliseconds from the system clock because that clock has them.
If the clock on the computer is wrong, Now is wrong. This page does not reach out to a network time service. For a signature that must agree with a server, trust the server’s clock or an agreed NTP source, not a tab that read Date.now().
Negative Unix seconds are allowed when they are whole numbers in range. They name instants before 1970. Some databases reject that. The page will still show the ISO form. Whether you should store it is a schema question, not a generator question.
Unix time is UTC. The local field uses this browser’s zone and is not a time-zone converter. Not a duration or age calculator.
Yes. Unix time is seconds since the UTC epoch, not a local wall clock.
No. Local means this browser’s zone only. There is no IANA picker.
Now shows both. Copy copies seconds. From Unix expects seconds.
No. Use the Time Duration or Date Difference calculators for spans.