Timers
Pick a duration and it starts immediately. Each one keeps time against your device’s clock rather than by counting ticks, so it stays accurate in a background tab, and sounds an alarm at zero.
Most used
Seconds
Minutes
Hours
Why these keep time when others drift
Browsers throttle background tabs hard — an interval that should fire every second may fire once a minute, or not at all. A timer that counts down by subtracting one each tick loses that time and finishes late, sometimes by several minutes.
These store the instant they should end at and work backwards from your device’s clock, so the interval only decides how often the display repaints. Throttle it as much as you like and the answer is still right the moment you look.