Android
Change Timer Sound auf Android
The timer in Android's Clock app plays a default tone until you pick a different one from the preinstalled list. This setting is separate from your alarm tone and your notification sounds, so changing it only affects the timer.
You find the option inside the Clock app itself, not in the system sound settings. Open Tap on Clock ➔ Open the menu ➔ Open the settings ➔ Tap on Timer sound ➔ Choose an option to browse the available tones and pick one.
When this setting will not help
If you hear no sound at all when the timer ends, the issue is usually the media or alarm volume, or a silent/Do Not Disturb mode that is still active, not the tone selection itself. Check your volume sliders and any active Focus mode first before changing the sound again.
The new tone applies to timers started after you save the change. Timers that are already counting down keep the sound that was active when you started them.