If you want more flexibility than the standard Windows or Mac settings, consider these popular free tools:

: A lightweight utility available in the Microsoft Store for users who want a simple countdown for music or long downloads. Built-in Alternatives (No Download Required)

: Go to Settings > System > Power & sleep (or Power & battery ) to adjust how quickly your screen turns off or the PC sleeps when idle.

A "sleep mode program" (spiashchii rezhim) typically refers to a utility that schedules when your computer enters a power-saving state or shuts down. While modern operating systems have these features built-in, third-party software offers more precise control, such as countdown timers or triggers based on network activity. Top Software Recommendations

: While primarily a "keep-awake" utility, it is the gold standard for Mac users who want to override default sleep settings based on app triggers or specific schedules.

: A highly-rated, open-source Windows app that lets you schedule sleep, hibernate, or shutdown with a clean, modern interface.