Where "now" comes from
The clock reads Date.now() from your own device. It is as accurate as your system clock, which is usually synchronised by NTP to within a few milliseconds. No time server is contacted. Browsers deliberately coarsen high-resolution timers, so the sub-millisecond digits of a "now" value are not meaningful. The nanosecond field is padded with zeros rather than invented.
Pause stops the display so you can copy a stable value. "Use in converter" loads the paused value into the converter, where every format and zone is available.
Testing with a fixed "now"
Relative descriptions such as "3 hours ago" depend on the current time. In settings you can override the reference time with any instant. Then relative outputs stay reproducible in screenshots, bug reports and test fixtures. The override is shown wherever it is in effect, so it never passes silently for the real clock.
Questions
- Is this the same timestamp a server would return?
- It is your device's clock. Servers and devices can disagree by seconds or more if one of them is not synchronised.
- How do I get the current epoch in code?
- The Code tab has snippets for 14 languages and query dialects: Date.now(), time.time(), Instant.now(), time.Now().Unix(), date +%s and more.
- When will the epoch reach 2,000,000,000 seconds?
- At 2033-05-18T03:33:20Z. Paste 2000000000 into the converter to check.