A region of a volatile memory can be dynamically resized based on a charge level of a backup battery supply. For example, a computing device can have a volatile memory with a memory region for storing data. The computing device can also have an attached backup battery supply. The computing device can determine a charge level of the backup battery supply and adjust a size of the memory region based on the determined charge level. Adjusting the size of the memory region can involve changing an amount of the volatile memory that is allocated to the memory region.