Show seconds in the Mac menu-bar clock

The menu-bar clock shows hours and minutes and stops there. To make it tick seconds too, flip one option in Control Center or run a single Terminal command. Either way the change lands the instant you make it, and turning it off is exactly as quick.

The one-toggle way

1. Open System Settings and click Control Center in the sidebar.
2. Scroll down to the Clock section and click Clock Options.
3. Turn on Display the time with seconds.

That's the whole job. The clock in the top-right corner starts counting immediately — no restart, no logout. The same sheet is where the day of the week, the date, AM/PM and the 24-hour switch live, so it's worth a look while you're there. This route works identically on macOS 13 Ventura, 14 Sonoma and 15 Sequoia; only the exact scroll position of the Clock section shifts slightly between them.

The Terminal one-liner

If you script your setup or just prefer the keyboard, the same preference has a name you can write to directly. The menu-bar clock is drawn by the ControlCenter process, so you nudge it to redraw afterward:

# Show seconds in the menu-bar clock
defaults write com.apple.menuextra.clock ShowSeconds -bool true
killall ControlCenter

The clock blinks off for a fraction of a second as the menu bar reloads, then returns with a seconds counter. To go back to a plain hours-and-minutes clock, write the opposite value and reload again:

# Undo — hours and minutes only
defaults write com.apple.menuextra.clock ShowSeconds -bool false
killall ControlCenter

Both commands are safe to re-run; defaults write just overwrites the one key it names and touches nothing else.

What the ticking clock is — and isn't

With seconds on, the clock redraws once a second instead of once a minute. On any Mac made in the last decade that's a rounding error in battery terms, but it's the reason Apple leaves seconds off by default — a static clock is one fewer thing repainting the menu bar. If you like the extra motion, you can pair it with flashing separators so the colon blinks on each tick; if you find a counter distracting, that same Clock Options sheet turns everything back to still in a click.

One thing to keep in mind: this is a wall clock, not a stopwatch. It shows the current time to the second, synced to your Mac's system clock, but it doesn't count elapsed time or let you start and stop it. For lap timing reach for the Clock app or a Shortcut. For knowing, at a glance, exactly what second it is right now, the menu-bar counter is the lightest tool there is.

Dress the rest of the clock

Seconds are one dial; the colon between the digits is another. If you want the separators to pulse on each tick for an even more alive-looking clock, see how to flash the clock separators on Mac.