Your system clock is eleven pixels tall in a corner you stopped noticing months ago. This one is as big as you like, in the font you like, in the middle of a page you open forty times a day.

Three formats: 24-hour, 24-hour with seconds, am/pm. Short on purpose. A free-text format field looks clever right up until someone mistypes it and the clock shows nothing at all.
Timezone is an offset, starting at "From my computer". Leave it and the clock follows your machine. Set it and it stays put. Three clocks in a row with city labels underneath is the standard move for anyone working across offices.
Drag the corner and the digits scale cleanly. No stretched bitmap. People run it anywhere between a discreet corner readout and half the screen.
Big sizes make the font matter more than the colour. Rubik Mono and Press Start hold their shape. The script faces look better at middling size beside a photo rather than sprawled across it.
Clock: what time is it. Date: what day is it. Countdown: how long have I got. Most finished themes carry at least two, because none of them answers the others' question.
Want the same information with more character? The flip clock animates every minute; the analog face trades precision for something you read at a glance.
The digital clock widget is part of New Tab Studio — free to install, no account needed to start.
Add to ChromeYes. Pick the "24h with seconds" format. The clock re-measures its own frame when you switch, so the rest of the layout does not jump.
Pick the am/pm format. It renders lowercase — 2:05 pm, not 2:05 PM.
No. The timezone is stored as a fixed offset in hours, so a clock set to London reads an hour behind through British Summer Time. Worth checking when the clocks change.