You close the lid at 100% and open it in the morning at 78%. A little overnight drop is normal — but a big one means your MacBook wasn’t really asleep.
How much sleep drain is normal?
In normal standby a modern MacBook loses only about 1–2% per hour, so a few percent overnight is fine. It’s common to lose a bit more in the first hour after you close the lid, while background tasks (Spotlight indexing, iCloud, Time Machine) finish up. Losing 10–20% or more overnight is the sign that something kept it awake.
Why your MacBook drains in sleep
- Power Nap: lets the Mac wake periodically to check mail, calendars and iCloud while asleep.
- “Wake for network access”: lets other devices and services wake the Mac over the network.
- Bluetooth or USB devices: a mouse, controller or hub can nudge the Mac awake — or stop it sleeping deeply.
- Login items & background agents: apps that launch at login can hold the Mac awake.
- Power assertions: an app can ask macOS to prevent sleep (the same mechanism as “keep awake”). A stuck or misbehaving app can hold this all night.
- The “hot bag” problem: if the lid is closed but the Mac keeps waking, it heats up in your bag and drains fast.
How to find what’s draining it
macOS records every sleep and wake locally. You can read it in Terminal with pmset -g log (look for Wake entries and the process that caused them), or check Console for power events. The catch is that the log is dense and the real culprit is usually buried among the timestamps.
How to reduce sleep drain
- Open System Settings → Battery → Options and turn off Power Nap and “Wake for network access” (on battery, at least).
- Review Settings → General → Login Items and remove anything you don’t need at startup.
- Unpair a flaky Bluetooth device that keeps waking the Mac.
- Fully quit any app known to hold the Mac awake before you close the lid.
- Keep macOS and your apps updated — sleep-drain bugs are common and often fixed in updates.
The easy way: let the app name the culprit
Mac 4 Breakfast’s Sleep Drain Detective does the detective work for you. It records your battery level when the lid closes and again at wake, reads the local power log, and names the apps that kept your Mac awake overnight — ranked by hours held, dark wakes counted — with a morning notch alert if you dropped more than your set threshold. Fully on-device; no root, no account. For daytime drain, see the draining-fast guide, or the full comparison.