v132 · performance

Freezing on Energy Saver

When Energy Saver is active, Chrome will freeze a "browsing context group" that has been hidden and silent for >5 minutes if any subgroup of same-origin frames within it exceeds a CPU usage threshold, unless it:

concepts

  1. Freeze on Energy Saver

    Battery-aware freezing of background tabs.

  2. what pauses

    Side-by-side counters — setTimeout, setInterval, requestAnimationFrame, fetch microtask — all stop together when the freeze hits.

  3. freeze simulator

    Slide hidden duration, audio state, CPU%, energy saver. The verdict updates live: would Chrome freeze this tab right now?

  4. API impact matrix

    16 web APIs, three categories: frozen, queued, exempt. Plus four app strategies to stay useful while frozen.

why it shipped

When users activate "Energy Saver", they expect the browser to adapt its behavior to maximize battery life. Tab freezing on Energy Saver helps meet that expectation by preventing background tabs that aren't actively used from consuming CPU excessively.

references