What is the average percentage of battery loss in an idle iPad Pro m4?

For one thing, the battery percentage indicator is like a car’s fuel gage. When the car (or iPad) is about 100% full, the drop in percentage proceeds slowly. Conversely, when nearly empty, the discharge rate appears much more rapid.

Your iPad will be running background housekeeping tasks while in its idle (sleeping/standby) state.

Battery utilisation is heavily influenced by the individual configuration of your iPad's settings and installed Apps. As rough benchmark, you might reasonably anticipate your iPad using ~10% of its total capacity across 24hrs while not being used. As such, unused, your iPad's battery will likely sustain the iPad for 7-10 days.

If instead your iPad is fully shut-down (stopping all background activity, except the internal clock), an healthy iPad battery will lose charge very slowly - only requiring a maintenance recharge after many months

If the iPad is shut down, I would expect a 10% loss or so after a week, assuming reasonable ambient temperature.

hurruuu wrote:

It isn[‘]t shut down

Why not?

Check Settings > Battery and learn what applications are consuming the power.