How long does a cell phone stay charged when turned off?

When a cell phone is turned off, it can typically hold its charge for several days to weeks, depending on factors like the battery's age, capacity, and environmental conditions. Modern smartphones have efficient power management systems that minimize battery drain when powered down. However, even in the off state, some minimal background processes may still use a small amount of battery. To maximize battery life, it's best to store the phone in a cool, dry place.